Module 02: Atoms and Elements

Question 1

What did John Dalton contribute to science in 1803?

Answer 1

Devised a way to indirectly observe atomic nature

1. temperature
2. atmospheric conditions
3. wind patterns

Question 2

What does the word “atom” mean?

Answer 2

Derived from the Greek term meaning “cannot be cut into smaller pieces”.

Question 3

What is Dalton’s Atomic Theory?

Answer 3

All matter is composed of extremely small particles → atoms

• Atoms of element: identical (size, mass, etc)
• not broken down into smaller pieces

Law of Conservation of Mass

Atoms cannot be subdivided, created, or destroyed

Law of Multiple Proportions

Atoms of different elements can combine > compound (whole-number ratio)

Question 4

What is the Law of Conservation of Mass?

Answer 4

Atoms cannot be subdivided, created, or destroyed

Question 5

What is the Law of Multiple Proportions?

Answer 5

Atoms of different elements can combine > compound (whole-number ratio)

Question 6

How did Dalton’s Theory prove durable?

Answer 6

Dalton’s original theory provides explanation to atomic structure. 200 years additional support for theory

Question 7

Define subatomic particles?

Answer 7

particles smaller than an atom

1. Protons
2. Neutrons
3. Electrons

Question 8

Explain how J. J. Thomson discovered electrons (1867-1906)?

Answer 8

Experiment:

• loved cathode rays
• discovered smaller, negative particles in an atom
• called: electrons

Conclusion:

Thomson hypothesized that these corpuscles were scattered within a positively charged atom

Question 9

Explain Ernest Rutherford’s contribution to the understanding of atoms (especially the nucleus)?

Answer 9

Who: Ernest Rutherford (student J. J. Thomson)

Experiment:

behavior particles as they were radiated onto a piece of gold foil

• some particles not pass strait through
• some scattered
• others bounced back

Conclusion:

Something big, positively charged in the center of the atom → nucleus

composed of protons and neutrons

Question 10

What contribution did James Chadwick make to the understanding of the nucleus?

Answer 10

Experiment:

• Found neutrons
• bombarded beryllium atoms with alpha particles → unknown radiation produced
• Neutral electrical charge

Conclusion:

determined neutron existed in an atom’s nucleus

mass close to the proton

Question 11

What conclusion did Crookes create related to cathode tubed?

How did Thomson challenge this idea?

Answer 11

Crookes’s Cathode:

Created cathode tube → allowed electrically charged particles flow between electrodes

Conclusion: something was traveling from the negative to the positive side

Thomson’s Electrons:

J. J. Thomas: used cathode ray tubes

negative attracted to the positive side & repelled by the negative side

calculate a mass-to-charge ration

Question 12

How did Rutherford’s discovery of the nucleus challenge Thomson’s hypothesis regarding electrons?

Answer 12

Assumed fast-moving alpha particles pass through piece of tin foil

if Thomas’s model was right nothing would scatter the rays

scattered particles indicated a nucleus

Question 13

Explain what the Bohr’s Quantum Model is:

Answer 13

Hypothesis:

The energy of a atoms not continue → only certain values

Proposal:

• emitting energy: higher to lower energy level
• absorbing energy: lower to higher energy level

Electrons:

• fixed energy
• only move

Energy Shell:

layers around the nucleus

1. 2 first
2. 8 second

Comparative to Solar System:

given away to the electron cloud model:

• orbitals
• brightness correlated to density

Question 14

How did Schrodinger and Heisenberg’s Electron Cloud Theory replace Bohr’s Quantum Model?

Answer 14

electrons not move in exact orbitals (like solar system)

Existed in the electron cloud

• region around the nucleus - mostly empty space - electrons orbit

Question 15

Define Atoms:

Answer 15

smallest unit of an element that retains the properties of that element

Question 16

How does the nucleus compare to the electron cloud?

Answer 16

NUCLEUS:

center

most of the mass

Protons:

• positively charged

Neutrons:

• neutral
• identifies the element

ELECTRON CLOUD

area around the nucleus

majority of the volume

Electrons:

• negative particles
• revolve around the nucleus
• ability move from one electron to another

Question 17

Define Ions:

Answer 17

atom/molecule with a positive or negative charge

Question 18

Define Isotopes:

Answer 18

atoms of the same element with different masses due to varying number of neutrons

Question 19

What is the overall charge of a atom?

Answer 19

Neutral

Question 20

Rutherford’s famous gold foil experiments shot heavy particles at a thin sheet of gold foil. What did he observe, and why did these observations eventually result in the addition of a nucleus to the atomic model? (3 points)

1. Some of the heavy particles bounced off the foil, because there are positive particles spread throughout the atom.
2. Some of the heavy particles bounced off the foil, because there is a dense, positive area in the atom.
3. The heavy particles all passed straight through the foil, because the atoms are mostly empty space.
4. The heavy particles all bounced off the foil, because the subatomic particles have mass and volume.

Answer 20

2.

Some of the heavy particles bounced off the foil, because there is a dense, positive area in the atom.

Question 21

Modern atomic theory states that atoms are neutral. How is this neutrality achieved? (3 points)

1. Equal number of neutrons and protons
2. Equal number of protons and electrons
3. More electrons than protons
4. More neutrons than electrons

Answer 21

2. Equal number of protons and electrons

Question 22

What is true of neutrons? (3 points)

1. They have no charge and are located inside the nucleus.
2. They have no charge and are located outside the nucleus.
3. They are negatively charged and are located inside the nucleus.
4. They are negatively charged and are located outside the nucleus.

Answer 22

1. They have no charge and are located inside the nucleus.

Question 23

In the 1800s, one of the statements in John Dalton’s atomic theory was that atoms are indivisible. Later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. What happened to the indivisible atom part of Dalton’s atomic theory, and why? (3 points)

1. The entire theory was discarded because Dalton’s scientific reputation was ruined once new evidence invalidated part of his theory.
2. The indivisible atom part of the theory was discarded because the consensus of data must exist for theories to be valid.
3. The theory remained unchanged because Dalton was correct regarding all other statements within the accepted scientific theory.
4. The theory remained unchanged because new data is discarded if it doesn’t fit within the accepted theory.

Answer 23

2. The indivisible atom part of the theory was discarded because the consensus of data must exist for theories to be valid.​

Question 24

Which hypothesis of Thomson’s atomic model was later found to be not true by Niels Bohr and why? (5 points)

Answer 24

J. J. Thomson discovered the electron. However, he concluded that the electrons were scattered within the positively charged atom. A few years later, Niels Bohr disproved Thomson’s hypothesis that elections were randomly scattered in the atom. Comparatively, he posed that electrons moved in orbits around the nucleus. Bohr’s hypothesis was built on Rutherford’s discovery of the atom. Rutherford disproved Thomson’s idea that there was an even distribution of particles in the atom; instead, there is a nucleus in the middle (which he found with hid tin foil experiment).

Hence, if there is a positively charged cluster of particles in the middle, there cannot be electron scattered the way Thomson proposed. So Bohr deduced from Rutherford’s theory of the nucleus that the atom had a “solar system” like structure (which was disproven by Schrodinger and Heisenberg later). The electrons, according to the Bohr, were ordered in layers - orbitals - around the nucleus.

Question 25

How does energy travel in waves?

Answer 25

The disturbance of the particles of a substance resulting in undulating motion

Question 26

What discovery did Max Planck make in relation to energy?

Answer 26

“Energy has both wavelike and particle-like properties”

No continuous energy but transfer in packets

Question 27

Define Quanta:

Answer 27

quantity of energy proportional in magnitude to the frequency of the radiation it represents

Question 28

What did Albert Einstein say about Plank’s theory regarding energy?

Answer 28

Agreed with Planck

Energy transferred discrete packets called quanta

Question 29

Define Radiation:

Answer 29

Emission of energy in the form of waves

• repetitive
• come various sizes
• carry energy

Question 30

Define Electromagnetic Wave:

Answer 30

Wave of energy generated by periodic fluctuation of an electromagnetic field

Question 31

Describe the structure of an electromagnetic wave?

Answer 31

Trough: lowest point

Crest: highest point

Amplitude: vertical distance between the crest/trough

measures height, intensity

Question 32

What is the speed of light?

Answer 32

3.0 * 10⁸ m/s

Question 33

Define wavelength:

Answer 33

Distance between corresponding points on adjacent waves

Consistent between the entire wave

Question 34

Define Frequency:

Answer 34

waves passing by a fixed amount of time (per second)

Hertz (Hz)

Question 35

What is the relation between wavelength and frequency?

Answer 35

inverse related

wave period → amount of time it takes for one wavelength to pass through a point ( seconds (s): Hz = 1/2)

Question 36

Define Wave Period:

Answer 36

amount of time it takes for one wavelength to pass through a point ( seconds (s): Hz = 1/2)

Question 37

Define Electromagnetic Radiation (EMR)?

Answer 37

Form of energy moves in a wavelike motion as it travels

fluctuating electric and magnetic energy field → oscillate at right angles to each other

Ex:

• visible light
• radio waves
• X-rays
• ultraviolet (UV) light
• gamma rays

Question 38

What is Radio Waves?

Answer 38

Used for radio, TV antennas, cell phones

Question 39

What are Micro-Waves?

Answer 39

Used in radar and to heat food (microwave)

Question 40

What are Infrared radiation?

Answer 40

HEAT → emitted by all objects (use special cameras to detect)

Question 41

What is Visible radiation?

Answer 41

All the radiation humans can see (light, sun, fire)

Question 42

What is Ultraviolet light?

Answer 42

Radiated by the sun (uses burns)

Question 43

Define X-rays:

Answer 43

Used in medical fields to look at bones on the inside

Question 44

Define Gamma Rays:

Answer 44

Radiation given off by radioactive substances

Question 45

Electrons have been shown to have both wavelike and particle-like properties. (4 points)

1. True
2. False

Answer 45

True

Question 46

Which type of electromagnetic radiation has a lower frequency than infrared radiation? (4 points)

1. Gamma rays
2. Microwaves
3. Visible light
4. X‒rays

Answer 46

2. Microwaves

Question 47

Compared to infrared radiation, an electromagnetic wave that has a lower frequency will also have a ________. (4 points)

1. longer wavelength and lower speed
2. longer wavelength and equal speed
3. shorter wavelength and lower speed
4. shorter wavelength and equal speed

Answer 47

2. longer wavelength and equal speed

Question 48

What is the frequency of a wave with a wavelength of 6.40 x 10⁴ meters? (4 points)

1. 1.87 x 10⁻⁶ Hz
2. 2.13 x 10⁻⁴ Hz
3. 4.69 x 10³ Hz
4. 1.92 x 10¹³ Hz

Answer 48

3. 4.69 x 10³ Hz

Question 49

Formula to determine wavelength:

Answer 49

Wavelength = Speed of Light / Frequency

Question 50

What happens to electrons of elements when heat/energy is added?

Answer 50

1. absorb energy
2. transition into a higher energy level

Question 51

How do electrons move between the excited and ground state?

Answer 51

Excited: particles has higher energy than lowest possible state

Ground: lowest energy state of atom

Question 53

What is an emission spectrum?

Answer 53

The transition between Excited <> Ground

1. emits light (different colors)
2. Emission spectrum: spectrum of electromagnetic radiation emitted by source

Question 54

How do heat, electricity, and light relate to an increase/decrease in energy?

Answer 54

Heat and Electricity → increases energy

Light → decrease in energy

Question 55

Define a “photon?”

Answer 55

Basic particle representing a quantum of energy

Question 56

What is a photon of light?

Answer 56

Emitted by an atom when electron transitions into lower energy level

Question 57

Define a photon of energy?

Answer 57

Amitted by an atom when electron transitions into lower energy level

Question 58

What is the formula for a energy of a photon?

Answer 58

E = hf

Directly proportional to the frequency of photon’s emission or absorption

• Joules
• h: Planck’s constant → 6.626 * 10^-34 (J *s)
• f: frequency of light
• Amount of energy → dependent on frequency of energy source

Question 59

Define a “scientific model:”

Answer 59

Visual representation of a scientific idea or process and make it easier to learn a new concept

Question 60

What are the different types of scientific models? (6)

Answer 60

Diagrams, Sketches, or drawings:

• Illustrations of processes
• Labels and icons

2D or 3D:

• Replicas of objects or processes
• ex: Model of a molecule

Simulations:

• Imitates a process to make it as realistic as possible

Infographics:

Explanatory pictures that improve understanding

Maps:

• Model landmarks, land elevations, weather, and more
• direction
• scale calculate distance
• legend to describe symbols and colors

Graphs

• Shows relationships

Question 61

What is the estimated effective nuclear charge (zeff) felt by the outer shell electrons in calcium (Ca)?

Answer 61

The outer shell electrons feel an estimated effective nuclear charge of about +2. This is because the total nuclear charge (+20) is shielded by the 18 core electrons in the energy levels closer to the nucleus. The equation +20 − 18 = +2 gives the estimated effective nuclear charge felt by each of sulfur’s outer shell electrons.

Question 62

Oxygen has a negative electron affinity. Does it absorb or release energy when it gains an electron?

Answer 62

When energy is released, the electron affinity value is represented as a negative value.

Question 63

A scientist needs to determine the reactivity of two elements. One element is a metal, and the other element is a nonmetal. What periodic trend determines the reactivity of both elements?

Answer 63

For metals, as you go down a column, the chemical reactivity increases. As you go right across a row, the chemical reactivity decreases.

For nonmetals, as you go down a column, the chemical reactivity decreases. As you go right across a row, the chemical reactivity increases.

Question 64

Do elements with a low effective nuclear charge also have low electronegativity? Explain your answer.

Answer 64

Outer shell electrons of elements with low effective nuclear charge usually have low electronegativity values because their nuclei exert a weak attractive force on electrons. However, this isn’t always true. There are exceptions on the periodic table.

Question 66

Define Quantum Model:

Answer 66

Mathematical model based on quantum theory that represents the probable state of electrons within an atom

Question 67

What was Niel Bohr’s proposal regarding electrons?

Answer 67

Niels Bohr Proposal: partials that circle the nucleus in shells

• lowest: n = 1
• Next: n = 2
• Number of electrons is equal to neutrons

Question 68

What is Heisenberg Uncertainty Principle?

Answer 68

Cannot know both the position and the velocity of particle at the same time

Question 69

What is the Principal Quantum Number?

Answer 69

Any whole number from 1-7

Energy levels around the nucleus

energy shells

• n =1 → inner most, least energetic
• energy increase and n increases

Question 70

What is the Angular Momentum Quantum Number (I)?

Answer 70

4 types of numbers

1. S orbital → round
2. P Orbital → shaped like a bumble
3. D orbital
4. F orbital

Question 71

Define subshells:

Answer 71

group of orbitals with the same potential energy

Question 72

Describe the ”s” orbitals from the Angular Momentum Quantum Number:

Answer 72

[1] S → one orbital

• spherical shape
• Electrons arrows
• up: clockwise spin
• down: counterclockwise

Question 73

Describe the “P” orbitals from the Angular Momentum Quantum Number:

Answer 73

[2] P → three orbitals

• dumbbell-shaped
• Max: 6 electrons

Question 74

Describe the “d” orbitals from the Angular Momentum Quantum Number:

Answer 74

[3] d → five orbitals

• nondescript shape
• max: 10 electrons

Question 75

Describe the “f” orbitals from the Angular Momentum Quantum Number:

Answer 75

[4] f → seven orbitals

• nondescript in shape
• Max: 14 electrons

Question 76

Define electron configuration:

Answer 76

: Arrangement of electrons in energy levels (shells) around nucleus

Question 77

Define the different parts of electron configuration: 1s²2s²2p⁶

1. Number of electrons
2. Oribtals
3. Energy Shells

Answer 77

1. Number of electrons: 1s²2s²2p⁶

• subshell has limit to the number of electron the orbit can hold
• Adding together = number of electron for element

2. Orbitals: 1s²2s²2p⁶
3. Energy Shells: 1s²2s²2p⁶

Question 78

Define each subshell’s corresponding amount of orbitals and electrons: (s, p, d, f)

Answer 78

See attachment:

Question 79

What are the [4] levels of configuration?

• Electrons
• Example
• type of subshell

Answer 79

Level 01:

• 2 electrons in s subshell
• Configuration: 1s²

Level 02:

• 8 electrons in p subshell
• Configuration: 1s²2s²2p⁶

Level 03:

• 18 electrons
• 2 electrons in s subshell
• 6 in p subshell
• 10 in d subshell
• 4s subshell is filled before 3d
• Configuration: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰

Level 04:

• 8 electrons
• 2 in 4s
• 6 in 4p
• Configuration: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶

Question 80

Define Ground-State Electron Configuration:

Answer 80

Arrangement that places electrons closest to nucleus

Question 81

What is the Aufbau Principle?

Answer 81

Quantum model of atom mathematically maps out an atom’s orbitals beyond ground state

“Electrons occupies that lowest energy orbital”

• Based on the potential energy of each position
• n = 1 first → lowest energy
• then: 2s, 2p, 3s

Question 82

What is the total number of electrons that can occupy the p sublevel? (3 points)

• 2 electrons
• 6 electrons
• 8 electrons
• 10 electrons

Answer 82

• 6 electrons

Question 83

Select the words that correctly fill in the blanks for this statement:
The p sublevel has ________ orbitals that are ________-shaped. (3 points)

1. three, dumbbell
2. three, spherical
3. five, dumbbell
4. five, spherical

Answer 83

1. three, dumbbell

Question 84

Which of the following is not a possible sublevel? (3 points)

• 1s
• 2p
• 3f
• 4d

Answer 84

3. 3f

Question 85

Magnesium (Mg) has an atomic number of 12. What is the ground-state electron configuration of magnesium? (3 points)

1. 1s²1p⁶2s²2p²
2. 1s²1p⁶1d⁴
3. 1s²2s²2p⁶3s²
4. 1s²2s²2p⁶2d²

Answer 85

3. 1s²2s²2p⁶3s²

Question 86

Which of the following is a reasonable ground-state electron configuration? (3 points)

1. 1s²2s²2p⁶3s²
2. 1s²2s²2p⁶3s²3d⁴
3. 1s²2s²2d¹⁰2p³
4. 1s²2s²2p³2d⁶

Answer 86

1. 1s²2s²2p⁶3s²

Question 87

The diagram shows four different locations in an atom.

Which locations are likely to have subatomic particles that are constantly in motion? (3 points)

1. 1 and 2
2. 2 and 3
3. 1 and 3
4. 2 and 4

Answer 87

4. 2 and 4

Question 88

A group of students designed a pamphlet. They used images and text to describe the chemical and physical changes that take place during cooking. Which type of scientific model did the students design? (3 points)

1. An infographic because it helps visualize the molecular motion during the changes in nature.
2. An infographic because the images improve understanding of the changes in matter.
3. A graph because it shows interrelationship between two types of changes.
4. A graph because it shows the effect of one variable on the other.

Answer 88

2. An infographic because the images improve understanding of the changes in matter.

Question 89

The partial electron configuration of an atom with 11 electrons is shown.

1s²2s²2p⁶X

Which of the following does X represent? (3 points)

1. 3s1
2. 2d1
3. 3p1
4. 4s1

Answer 89

1. 3s1

Question 90

Define Coulomb:

Answer 90

abbreviated as C; unit of charge

Question 91

What is Coulomb’s Law?

Answer 91

Coulomb’s law: the force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the separation distance

Question 92

Define Electric Field :

Answer 92

a region around a charged particle or object that applies a force on other charged particles or objects

Question 93

Define Electric field lines:

Answer 93

a pattern of lines that point in the direction a positive charge would follow

Question 94

Define Electrostatic Forces:

Answer 94

the attractive and repulsive forces between opposite or matching charges

Question 95

What was Hund’s first rule?

Answer 95

orbitals within the same sublevel, with equal energy, are each occupied by one electron before any orbital in that sublevel is occupied by a second electron

Question 96

What was Hund’s second rule?

Answer 96

electrons within the same orbital spin in opposite directions

Question 97

Define Orbital notation:

Answer 97

a visual representation of electron configuration using lines and arrows for orbitals and electrons

Question 98

What was Pauli exclusion principle?

Answer 98

no two electrons in the same atom can have the same set of four quantum numbers

Question 99

What are the four parts of the Pauli Exclusion Principle?

Answer 99

1. Principle Quantum Number (n)
2. Angular Momentum Quantum Number (l)
3. Magnetic Quantum Number (m_l)
4. Spin Quantum Number (m_s)

Question 100

What does the Angular Momentum Number indicate?

Answer 100

The sublevel/type of orbital

Question 101

Define the following for n = 1:

• Name of subshells
• Angular Momentum Quantum Number
• Total electron in energy level

Answer 101

Subshell energy level: s

Angular Momentum Quantum Number: l = 0

Total electrons: 2

Question 102

Define the following for n = 2:

• Name of subshells
• Angular Momentum Quantum Number
• Total electron in energy level

Answer 102

Subshell energy level: s, p

Angular Momentum Quantum Number: l = 0, l = 1

Total electrons: 8

Question 103

Define the following for n = 3:

• Name of subshells
• Angular Momentum Quantum Number
• Total electron in energy level

Answer 103

Subshell energy level: s, p, d

Angular Momentum Quantum Number: l = 0, l = 1, l = 2

Total electrons: 18

Question 104

Define the following for n = 4:

• Name of subshells
• Angular Momentum Quantum Number
• Total electron in energy level

Answer 104

Subshell energy level: s, p, d, f

Angular Momentum Quantum Number: l = 0, l = 1, l = 2, l = 3

Total electrons: 32

Question 105

What is the Magnetic Quantum Number?

Answer 105

Represents the specific orbital an electron is likely to occupy

• The range of magnetic quantum numbers for a given sublevel (l) is from −l to +l.*
• For example, in an s sublevel (l = 0) there is only one available orbital. It has a magnetic quantum number of ml = 0. A p sublevel (l = 1) has three orbitals with magnetic quantum numbers of ml = −1, 0, +1. The orbital notation examples in the table show how the magnetic quantum numbers relate to the 3D shape, orientation, and number of orbitals in a sublevel.​*

Question 106

Define the following for s sublevel: ( l = 0)

• Magnetic Quantum Number
• Number of Orbitals
• Shape

Answer 106

• Magnetic Quantum Number: 0
• Number of Orbitals: 1
• Shape: spherical

Question 107

Define the following for p sublevel: ( l = 1)

• Magnetic Quantum Number
• Number of Orbitals
• Shape

Answer 107

• Magnetic Quantum Number: -1, 0, 1
• Number of Orbitals: 3
• Shape: Dumbbell

Question 108

Define the following for d sublevel: ( l = 2)

• Magnetic Quantum Number
• Number of Orbitals
• Shape

Answer 108

• Magnetic Quantum Number: -2, -1, 0, 1, 2
• Number of Orbitals: 5
• Shape: Double Dumbbell

Question 109

Define the following for f sublevel: ( l = 3)

• Magnetic Quantum Number
• Number of Orbitals
• Shape

Answer 109

• Magnetic Quantum Number: -3, -2, -1, 0, 1, 2, 3
• Number of Orbitals: 7
• Shape: Multiple Lobes

Question 110

What is the Spin Quantum Number?

Answer 110

A combination of other three Pauli Exception Principles is used to determine location of the electron

• first 3 quantum numbers → same orbital value
• 4th quantum number: Spin Quantum Number
• Identify the specific electron within the orbital

Hund’s second Rule:

Electrons within the same orbital spin in opposite directions

• 2 negatively charged electrons located near each other are most stable
• Option: +1/2 or -1/2

Question 111

What is Orbital Notation Diagrams? How does it relate to Hund’s First Rule?

Answer 111

Hund’s First Rule:

Orbitals of equal energy are each occupied by one electron → spinning in the same direction

Arrows: (↑ ↓) used represent electrons

Example:

• Hydrogen → one electron found in 1st orbital → (↑)
• Helium → two electrons in first orbital → (↑ ↓)
• Lithium → three electrons (*two in first orbital and one in 2nd orbital) → *(↑ ↓) (↑)

Question 112

What are electron Forces?

Answer 112

Electron charge:

• physical property of matter
• causes particle to experience force
• Electrostatic force creates electrical field

OPPOSITE forces = attract

SIMILAR forces = repel

Question 113

What is atomic charge?

Answer 113

The electrostatic force between subatomic particles = massive

• influences arrangement
• electron spin: two electrons cannot spin in the same orbital spin

Electron >< Nucleus

Electron <> Electron

Question 114

What is the electron force between atoms?

Answer 114

Neutral Atom: positively charged particles (protons) equals number of negative charged particles (electrons)

net charge: 0

When electron moved between atoms:

• one loses electron → a +1 charge
• gains electron → a - 1 charge

creates electrical charge between atoms

Question 115

What is Coulomb’s Law of Electrical Forces?

Answer 115

Distance between charged particles decrease, force increases and visa versa

Force between two charges:

• directly proportional to product of charges
• inversely proportional to square of separation distance

Question 116

Define Nuclear Charge:

Answer 116

Objects closer to each other / larger product of electrical charge = experience stronger electrostatic forces

• net positive charge associated with protons in nucleus → nuclear charge
• electrons close to the nucleus > n = 1

Question 118

What was Democritus’s contribution to the periodic table?

Answer 118

• thought substances made up small items
• not broken smaller pieces
• indivisible unit

Question 119

What was Aristotle’s contribution to the periodic table?

Answer 119

Fundamental elements: Earth, Fire, Water, Air

Mixed to create new materials → Alchemy

Question 120

What was Robert Boyle’s contribution to the periodic table?

Answer 120

Scottish alchemist

Atoms are different sizes and shapes

Question 121

What was Antione Laurent de Lavoisier’s contribution to the periodic table?

Answer 121

First modern definition of an element

Chemical substance not broken down into another substance

names 30 elements

Question 122

Who was the first person to create a “periodic table” was understood today?

How was this accomplished?

Answer 122

First to create the “Periodic table” : Dmitri Mendeleyev

• noticed repeating pattern
• 1869
• Rows and columns

Question 123

What are the differences between metals and non-metals?

Answer 123

Metals

• good conductors of electricity and heat
• solid at room temperature
• malleable, flexible, and ductile
• Shiny (lustrous)
• Higher density
• The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive.

Nonmetals

• poor conductors
• Solid, liquid, or gas at room temperature
• Solids are brittle and break easily
• Dull
• Lower density

Question 124

What are metalloids?

Answer 124

Properties of both metals and solid nonmetals

Question 125

What are the 4 types of metals on the periodic table?

Answer 125

1. Alkali Metals
2. Alkaline Earth Metals
3. Transition Metals
4. Mixed

Question 126

What are the differences between rows and periods?

Answer 126

Row: periods → same number of electron shells

Column: groups or families→ same number of electrons in outer shell

Question 127

What are the three consecutive parts of this element called and what are these value’s purposes?

Answer 127

196.9665 u: Atomic Number

• Measured: atomic mass units (amu)
• comes from protons and neutrons

Au: Chemical Symbol

• (sometimes) first 1 or 2 letters

79: Atomic Number

• Arranged in this order
• Indicated the number of protons

Question 128

What is the mass number?

Answer 128

not found on the periodic table

Counting the protons and neutrons in specific isotope of the element

round the atomic mass to the nearest whole number

Question 129

How are the number of neutrons in an element determined?

Answer 129

Mass - Atomic Number

Question 130

What are non-metals (on periodic table)?

Answer 130

Hydrogen, carbon, nitrogen, oxygen, fluorine, phosphorous, sulfur, chlorine, bromine, iodine, and selenium.

• brittle (when solid)
• not conductible
• not reflective
• dull

Question 131

What are the properties of the alkali metals?

Answer 131

Group 01

1. soft and shiny
2. reactive
3. mostly combined with other metals

Question 132

What are the properties of the Alkaline Earth Metals?

Answer 132

beryllium, magnesium, calcium, strontium, barium, and radium.

• Harder and denser than Alkali metals;
• less reactive than Alkali

Question 133

What are the properties of transition metals?

Answer 133

21-112 & Column 3-12

• Include: lanthanides and actinides
• special trait is their ability to transition in charge when they form ions

a. Lanthanide Series:

• soft, rare-earth metals
• transition metal category
• atomic numbers 57-71
• Known for silvery color
• hard to find in environment

b. Actinides Series:

• Human-made (not in nature)
• transition metals
• 89-103

Question 134

What are the Lanthanide Series?

Answer 134

• soft, rare-earth metals
• transition metal category
• atomic numbers 57-71
• Known for silvery color
• hard to find in environment

Question 135

What are the Actinides Series?

Answer 135

• Human-made (not in nature)
• transition metals
• 89-103

Question 136

What are the Post Transition Metal group?

Answer 136

aluminum, gallium, indium, tin, thallium, lead, bismuth, and elements with atomic numbers 113 through 116.

• Opaque (milky)
• Solids
• not conductible

Question 137

What are the Metalloids?

Answer 137

• boron, silicon, germanium, arsenic, antimony, tellurium, and polonium.*
• Properties of metals and nonmetals

Question 138

What are the Halogens?

Answer 138

fluorine, chlorine, bromine, iodine, tennessine, and sometimes astatine, which is also considered a metalloid.

• non-metals
• reactive → easily bond multiple materials
• Can go through phase change at room temperature

Question 139

What are the Noble Gasses?

Answer 139

helium, neon, argon, krypton, xenon, radon, and oganesson.

• Unreactive
• non-metal gases

Question 140

How do isotopes (mass-wise) differ from elements?

Answer 140

same amount of protons

different amount of neutrons → different mass

Question 141

Formula for Average Atomic Mass:

Answer 141

(percent abundance × mass) + (continue for each isotope) = average atomic mass

Question 142

What are the two ways isotopes are represented?

Answer 142

1. dash to the right of the name with the mass number (uranium-235)
2. Mass number as superscript to upper left of the chemical symbol and place atomic number as a subscript

Question 143

Mendeleev used his arrangement of elements in order of increasing mass and repeated properties to predict the mass and properties of undiscovered elements. (2 points)

True

False

Answer 143

True

Question 144

Helium (He), oxygen (O), carbon (C) fluorine (F), and chlorine (Cl) are all nonmetals. Using the periodic table, which pair of nonmetals do you predict has the most similar properties, and why? (3 points)

1. Oxygen and chlorine, because they are both alkalis
2. Helium and carbon, because they are both noble gases
3. Oxygen and fluorine, because they are in the same period
4. Fluorine and chlorine, because they are both halogens

Answer 144

4. Fluorine and chlorine, because they are both halogens

Question 145

A student observes that an element is shiny, bends easily, and can conduct electricity. What type of element is the student most likely observing? (3 points)

1. Gas
2. Metal
3. Metalloid
4. Nonmetal

Answer 145

2. Metal

Question 146

Nickel has the chemical symbol Ni and the atomic number 28. How many protons, neutrons, and electrons would be found in an atom of nickel-78? (3 points)

1. 28 protons, 28 neutrons, 50 electrons
2. 28 protons, 50 neutrons, 28 electrons
3. 50 protons, 28 neutrons, 50 electrons
4. 50 protons, 50 neutrons, 28 electrons

Answer 146

2. 28 protons, 50 neutrons, 28 electrons

Question 147

An atom has atomic number 5 and mass number 11. How many neutrons does the atom have? (3 points)

• 5
• 6
• 10
• 11

Answer 147

6

Question 148

The image shows the representation of an unknown element in the periodic table.

Based on the representation, which of the following statements about the element is true? (3 points)

1. The total number of protons plus electrons is 10.
2. The number of neutrons in an atom of the element is 20.
3. The sum of the masses of protons and neutrons is 20.1797.
4. The mass of only the protons in the nucleus is 20.1797.

Answer 148

3. The sum of the masses of protons and neutrons is 20.1797.

Question 149

Zinc has the chemical symbol Zn and the atomic number 30. How many protons, neutrons, and electrons does an atom of zinc-69 have? (3 points)

1. 30 protons, 39 neutrons, 39 electrons
2. 39 protons, 30 neutrons, 30 electrons
3. 39 protons, 30 neutrons, 39 electrons
4. 30 protons, 39 neutrons, 30 electrons

Answer 149

4. 30 protons, 39 neutrons, 30 electrons

Question 150

An atom has atomic number 5 and mass number 11. How many protons does the atom have? (3 points)

• 5
• 6
• 10
• 11

Answer 150

5

Question 151

The image shows the representation of an unknown element in the periodic table.

Based on the representation, which of the following statements about the element is true? (3 points)

1. The number of neutrons in an atom of the element is 24.
2. The combined mass of all the protons and electrons is 24.305.
3. The combined mass of all the neutrons and electrons is 24.305.
4. The mass number of the most common isotope of the element is 24.

Answer 151

4. The mass number of the most common isotope of the element is 24.

Question 152

What relationship exists between protons and the atomic number?

Answer 152

Direct Relationship

Question 153

What is an effective nuclear charge?

Answer 153

(Z_eff) nuclear charge felt by outer shell electrons after considered the number of shielding electrons that surround the nucleus

Positions of electrons within atoms influenced by nucleus

• felt by outer shell electrons
• shielded by inner core electrons

Question 154

What are electrostatic forces:

Answer 154

Forces between particles due to their electrical charge

1. electrons repel each other
2. proton and electron attract

Question 155

Define “Screening constant:”

Answer 155

Value represents number by core electrons within atom

Question 156

What is a nuclear charge?

Answer 156

Net positive charge of nuclear of atom

Question 158

How is the nuclear charge felt by outer shell electrons determined?

Answer 158

Total nuclear charge - shielding (core) electrons

Question 159

What are the [3] trends of effective nuclear charge across the periods of the Periodic table?

Answer 159

[1] Overall nuclear charge increase +1 → each additional proton

[2] Each atom:

1. additional electron in outer energy
2. number core electrons lower energy levels remain constant

[3] Screening constant stay the same

• Sulfur: zeff = +16 − 10 = +6
• Phosphorus: zeff = +15 − 10 = +5

Question 160

What are the [2] trends of effective nuclear charge down groups of the periodic table?

Answer 160

1. Protons increase down a group

• greater attraction between protons and outer shell electrons
• electrons pulled inwards

2. Size of atoms and number of core electrons

• increase down group
• increase number of shielding electrons

Question 161

What is the atomic radius?

Answer 161

Measured the size of an atom.

Measure the distance between nuclei of two bonded atoms of the same element and divide it by half

Distance between nuclei ÷ 2

Question 162

What two trends are evident looking at atomic radii?

Answer 162

1. Atomic radius increases moving down column/group
2. Atomic radius decreases moving across the row from left to right

Question 163

Define Ionization Energy:

Answer 163

the energy required to remove one electron from atom = positive ion

• elements with lower effective nuclear charge → less energy required to give up electron = less ionization energy

Question 164

How does an increase in ionization energy compare to that of an effective nuclear charge?

Answer 164

Direct relationship

Question 165

What are the trends of ionization energy on the periodic table?

Answer 165

1. Increases from left to right and moving up a group on periodic table
2. decreases down (as atom size increases)

Question 166

What are the two types of Ionic Radii?

Answer 166

Electrons: subatomic particles gained or lost = ions

1. Cations: positive charged + loss of electrons
2. Anions: negative charge + gain of electrons

Question 167

How do the ionic radii of metals and non-metals compare?

Answer 167

Metals: cations

smaller neutral atoms

losing one+ electron

Nonmetals: anions

larger than neutral atoms by gaining one+ electrons

Question 168

What are the three trends of ionic radii on the periodic table?

Answer 168

1. Decreases from left to right within metals
2. Decreases from left to right in nonmetals
3. Increases down a group

Question 169

Define Electronegativity:

Answer 169

Measure the attraction of electron in chemical bond

• predict how elements and compounds interact during chemical reactions
• Higher → greater attraction

Question 171

What is the relation between electronegativity and effective nuclear charge?

Answer 171

Elements with high effective nuclear charge: strong attraction outer shell → strong electronegativity

Direct relationship

Question 172

On what scale is electronegativity measured?

Answer 172

Scale to measure: 0.0 → 0.4

• noble gasses > lowest
• Lowest on periodic table: (0.7) cesium (Cs) & francium (Fr)

Question 173

Define Chemical Reactivity:

Answer 173

Readiness of substance to undergo chemical change

Question 174

Compare Chemical Reactivity in metals and non-metals:

Answer 174

Metals:

1. lowest in column → increased reactivity
2. Right in row → decreased reactivity

Nonmetals:

1. down column → decreased reactivity
2. right in row → increased reactivity

Question 175

Define Electron Affinity

Answer 175

the energy involved when neutral atoms gain electrons

• Take electrons → release energy (represented by negative value)
• Absorbs energy → accepts electron

not stable

loss electron spontaneously

Question 176

What are the two Electron Affinity trends on the periodic table?

Answer 176

1. More negative across period from group 1 to 17

relates to increase in effective nuclear charge

2. Not obvious moving down
   (generally) more positive down a group

lot of exceptions

Question 177

A cation is larger than it was as a neutral atom because the added electrons occupy a higher energy level. (4 points)

• True
• False

Answer 177

False

Question 178

As you move down group one of the periodic table, what happens to the atomic radii? (4 points)

1. They increase, because of the higher number of occupied energy levels.
2. They increase, because of the stronger attraction between electrons and the nucleus.
3. They decrease, because of the weaker effective nuclear charge.
4. They decrease, because of the lower number of protons.

Answer 178

1. They increase, because of the higher number of occupied energy levels.

Question 179

Which of the following elements would you expect to have the lowest ionization energy value, and why? (4 points)

1. Fluorine (F), because it is a halogen that naturally forms a negative ion
2. Lithium (Li), because it has a low effective nuclear charge and large radius
3. Neon (Ne), because it is a noble gas with a full energy level and small radius
4. Nitrogen (N), because it is a nonmetal that does not have a full outer energy level

Answer 179

2. Lithium (Li), because it has a low effective nuclear charge and large radius

Question 180

Where are the most reactive metals located? (4 points)

1. Upper left of periodic table
2. Lower left of periodic table
3. Upper right of periodic table
4. Lower right of periodic table

Answer 180

2. Lower left of periodic table

Question 181

The image compares the arrangement of electrons in two different neutral atoms.

Which of the following best explains the position of the two atoms in the periodic table? (4 points)

1. Both atoms have an estimated Zeff of 1; therefore, Atom D is to the right of Atom E in the same period.
2. Both atoms have Zeff of 1; therefore, Atom D is above Atom E in the same column because of the additional energy level.
3. Atom D has an estimated Zeff of 1 and is therefore to the left of Atom E, which has a Zeff of 9.
4. Atom D has an estimated Zeff of 1 and is therefore below Atom E in the same column, which has a Zeff of 9.

Answer 181

2. Both atoms have Zeff of 1; therefore, Atom D is above Atom E in the same column because of the additional energy level.

Question 182

Answer the following about Robert Boyle

1. Contributions
2. Innovations
3. Further Studies

Answer 182

Chemist/Physicist (1627-1691), Ireland

Contributions:

• Inverse relationship between volume and pressure of gas
• Wrote first textbook about the study of substances

Innovations:

• Theorized that all matter & changes are due to particle motion

Further Studies:

• Behavior of gases and atomic theory

Question 183

Answer the following about Joseph Proust:

1. Contributions
2. Innovations
3. Further Studies

Answer 183

Chemist (1754-1826); France

Contributions:

• Water always has a two-to-one ratio of hydrogen to oxygen

Innovations:

• Law of Definite Proportions
• chemical compound will always have its own characteristic ratio of components

Further Studies:

• supported John Dalton
• Led to current atomic theory

Question 184

Answer the following about Antoine Lavoisier:

1. Contributions
2. Innovations
3. Further Studies

Answer 184

Chemist (1743-1794); France

Contributions:

• Metric system
• Rules for naming chemical compounds

Innovations:

• Law of Conservation of Mass
• chemical elements hold their mass in chemical reactions

Further Studies

• Numerous studies on matter & substance interaction

Question 185

Answer the following about John Dalton:

1. Contributions
2. Innovations
3. Further Studies

Answer 185

Chemist/Physicist/Meteorologist (1766-1844); England

Contributions:

• Meteorology
• Behavior of gasses
• Atomic theory

Innovations:

• Law of Particle Pressure:
• postulate for atomic theory

Further Studies:

• Atoms and sub particle studies

Question 186

Answer the following about Marie and Pierre Curie:

1. Contributions
2. Innovations
3. Further Studies

Answer 186

Chemist/Physicist (1867-1934)(1859-1906); Poland and France

Contributions:

• Elements emit energy at certain rate
• Pioneers in study of radiation

Innovations:

• Nobel Prize (shared with Becquerel) 1903 → discovered radioactivity
• Marie first women to win Nobel Prize for 2 difference sciences

Further Studies:

• radioactive materials
• uses in medical applications (X-rays)

Question 187

Answer the following about Max Planck:

• Contributions
• Innovations
• Further Studies

Answer 187

Physicist (1858-1947); Germany

Contributions:

• Atoms consist of smaller particles
• Energy emitted in discrete units (quanta) not continuous waves

Innovations:

• Planck’s Constant
• quantum theory
• calculate energy and frequency

Further Studies:

• studies of atoms and sub-particles
• discovery photons

Question 188

Answer the following about Ernest Rutherford:

1. Contributions
2. Innovations
3. Further Studies

Answer 188

Physicist (1871-1937); England

Contributions:

• Demonstrated that atoms consist of tiny, dense, positively charged regions

Innovations:

• “Father of Nuclear Physics”
• discovered atomic nucleus

Further Studies:

• further studies by Bohr, Chadwick,

Question 189

Answer the following about Neils Bohr:

1. Contributions
2. Innovations
3. Further Studies

Answer 189

Physicist (1885-1962); Denmark

Contributions:

• Photons emitted from atoms
• Electrons exist in energy shell

Innovations:

• electrons have distinct energy levels
• light is emitted when electrons change energy levels

Further Studies:

• theorized atoms had positive charge and orbiting electrons

Question 190

What contribution did Albert Einstein make to nuclear studies in 1905?

Answer 190

1905: Albert Einstein (German)

equation for nuclear power (E = mc²)

Question 191

Explain how nuclear fission was discovered and by whom:

Answer 191

1938: Otto Hahn & Frizt Strassman (German) and Lise Meitner + nephew Otto Frisch (Sweden)

experiments with nuclear fission

Hahn and Strassman:

• shot elements with neutrons → uranium broken into two
• combined mass less than whole uranium

Meitner and Frisch:

• theorized that the loss of mass pointed to a splitting process released energy
• nuclear fission

Question 192

What is the difference between Nuclear Fission and Nuclear Fusion?

Answer 192

Nuclear Fission

• Break apart → release energy

Nuclear Fusion

• Combining (fusing) atoms → even more energy
• joined nuclei two light elements
• reaction powers starts

Question 194

Which of the following is a characteristic of durable scientific knowledge? (4 points)

1. It remains unchanged over time.
2. It is rarely subjected to examination.
3. Several scientists’ investigations support it.
4. Similar investigations yield dissimilar results.

Answer 194

3. Several scientists’ investigations support it.

Question 195

Which of the following provides evidence to support Bohr’s theory of atomic orbitals? (4 points)

1. Gold foil experiment
2. Plum pudding model
3. Spectrum of colors emitted by gas
4. Radiation produced when beryllium is bombarded with alpha particles

Answer 195

3. Spectrum of colors emitted by gas

Question 196

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? (4 points)

1. Some uncharged particles are scattered by a gold foil.
2. All uncharged particles are attracted towards a gold foil.
3. All positively charged particles pass straight through a gold foil.
4. Some positively charged particles bounce back from a gold foil.

Answer 196

4. Some positively charged particles bounce back from a gold foil.​

Question 197

The table compares the masses of three unknown subatomic particles.

Which particle is most likely present in the nucleus of the atom? (4 points)

1. Only particle P
2. Only particle Q
3. Both particles Q and R
4. Both particles P and R

Answer 197

4. Both particles P and R

Question 198

The table shows the number of charged particles in an ion.

A negatively charged substance is brought near the ion. What will most likely happen and why? (4 points)

1. The ion will repel the substance because it has more electrons than protons.
2. The ion will repel the substance because it has more protons than electrons.
3. The ion will attract the substance because it has more electrons than protons.
4. The ion will attract the substance because it has more protons than electrons.

Answer 198

4. The ion will attract the substance because it has more protons than electrons.

Question 199

What is the lowest point of a wave called? (4 points)

1. Amplitude
2. Crest
3. Frequency
4. Trough

Answer 199

4. Trough

Question 200

Two friends at different locations want to communicate with each other by sending low energy signals. Which of the following methods can they use to communicate? (4 points)

1. Produce x‒rays using colliding electrons and send them to radios, which capture sound.
2. Send messages using infrared radiations, which travel in the form of waves.
3. Send radio waves through intervening media like radio and television.
4. Produce sound waves using microwaves from heated objects.

Answer 200

3. Send radio waves through intervening media like radio and television.

Question 201

What term is used to describe the energy level of any level higher than the ground state of a particle? (4 points)

1. Photon state
2. Excited state
3. Higher state
4. Emission state

Answer 201

2. Excited state

Question 202

An electron moved from a lower energy level to a higher energy level. What most likely happened during the transition? (4 points)

1. A random amount of light was released.
2. A fixed amount of energy was absorbed.
3. A fixed amount of energy was released.
4. A random amount of light was absorbed.

Answer 202

2. A fixed amount of energy was absorbed.

Question 203

Define the principal quantum number. (8 points)

Answer 203

The principal quantum number (denoted by n) is one part of the Pauli Exclusion Principle (the other three are:

• the angular momentum quantum number (n),
• the magnetic quantum number (ml),
• the spin quantum number (ms)

The principal quantum number is used to indicate the energy levels that circle the nuclear.

• the symbol n starts at n = 1, which is the innermost, least energetic energy shell, and increases up until n = 7, which is the most energetic, and farthest from the nucleus.
• The principal quantum number can indicate what the other qualities of the electrons surrounding the nucleus of atoms; for example, if n = 1, then the angular momentum quantum number is l = 0, while the subshell is “s,” and there are 2 electrons in the energy level.
• The electrons in n = 2, n = 3, and n = 4, is 8, 18, and 32 respectively.

Therefore, the principal quantum number is used to denote the energy level an atom is in, which is used to determine the number and position of electrons in each energy level; however, according to the Heisenberg Uncertainty Principle, the position and velocity of a particle cannot be determined at the same time.

Question 204

The table compares the number of electrons in two unknown neutral atoms.

Use this information to determine the number of valence electrons in the atoms. Which of the following correctly compares the stability of the two atoms? (4 points)

1. Both are unreactive.
2. Both are highly reactive.
3. A is unreactive and D is reactive.
4. A is reactive and D is unreactive.

Answer 204

1. Both are unreactive.

Question 205

A substance is present in the gaseous state at room temperature. Which of the following best explains the probable position of the substance in the periodic table? (4 points)

1. It is between groups 1 to 12 because it is a metal.
2. It is between groups 13 to 18 because it is a metal.
3. It is between groups 1 to 12 because it is a non-metal.
4. It is between groups 13 to 18 because it is a non-metal.

Answer 205

4. It is between groups 13 to 18 because it is a non-metal.

Question 206

Which of the following groups of elements are likely to have substances that have both metallic and non-metallic properties? (4 points)

1. Actinides
2. Group 18
3. Lanthanides
4. Group 14

Answer 206

4. Group 14

Question 207

Describe the properties of alkaline earth metals. Based on their electronic arrangement, explain whether they can exist alone in nature. (8 points)

Answer 207

Alkaline earth metals:

1. exist in Group 02 on the periodic table
2. are extremely reactive (in correlation with the period trend that elements towards the bottom left are the most reactive).

Though they are similar to the alkali metals (Group 01), they are somewhat less reactive and denser and harder.

Their electronic arrangement makes them very reactive, meaning that they cannot exist alone in nature, but they are commonly found in compounds because they react easily.

For example, Magnesium (Mg) has 12 electrons, meaning that the first energy shell has 2 electrons. The second has 8 electrons, and the third (which will also require 8 to be stable) only has 2. Because the valence electron for Magnesium is only 2 (the more valence electrons there are, the most stable an element is), the element is highly reactive.

Since it is highly reactive, it is more likely to chemically bond with another element to create a compound, so few alkaline earth metals exist alone in nature.

Question 208

Which of the following properties decrease down a column in the periodic table? (4 points)

1. Effective nuclear charge
2. Ionization energy
3. Atomic radii
4. Ionic radii

Answer 208

2. Ionization energy

Question 209

Which of the following correctly compares the radii of Na and Na⁺? (4 points)

1. Na has a smaller radius than Na⁺ because Na has expanded its electron cloud.
2. Na has a larger radius than Na⁺ because Na has lost its outermost energy shell.
3. Na has a smaller radius than Na⁺because Na⁺ has expanded its electron cloud.
4. Na has a larger radius than Na⁺ because Na⁺ has lost its outermost energy shell.

Answer 209

4. Na has a larger radius than Na⁺ because Na⁺ has lost its outermost energy shell.

Question 210

Which of the following explains how Marie and Pierre Curie tried to influence the use of their discovery? (4 points)

1. They supported the use of radioactive elements in generating inexpensive power.
2. They opposed the use of energy released during nuclear fission at the time of war.
3. They supported the use of radioactive elements for medical diagnostic purposes.
4. They opposed the use of nuclear fusion during the Manhattan Project.

Answer 210

4. They supported the use of radioactive elements for medical diagnostic purposes.

Question 211

Which of the following is true for a reliable scientific source? (4 points)

1. It cites logic.
2. It cites opinions.
3. It cites valid data.
4. It cites common sense.

Answer 211

3. It cites valid data.

Question 212

Which quantum number describes the subshell of an electron? (4 points)

1. Spin quantum number
2. Principal quantum number
3. Magnetic quantum number
4. Angular momentum quantum number

Answer 212

4. Angular momentum quantum number

Question 213

How many orbitals are in the f sublevel? (4 points)

1. 7
2. 5
3. 3
4. 1

Answer 213

1. 7

Question 214

How many electrons in an atom can have the quantum numbers n = 4, l = 0, ml = 0, ms = +1/2? (4 points)

1. 1
2. 2
3. 3
4. 6

Answer 214

1. 1

Question 215

Describe the orbital diagram of an atom with 16 electrons. Explain how this orbital diagram demonstrates Hund’s rule. (8 points)

Answer 215

The first rule to consider for drawing an atom’s orbital diagram is the Aufbau Principle, which states the arrangement of electrons is as close to the nucleus as possible. Since there are 16 electrons, the configuration will look as follows: 1s²2s²2p⁶3s23p4.

Furthermore, according to the Pauli Exclusion Principle, there will be 3 energy levels (n = 3), so the angular momentum quantum number will be l = 0, l = 1, l = 2 (the subshells will be s and p). Next, since there are three orbitals (energy levels), the magnetic quantum number will be -1, 0, and +1.

To determine the spin quantum number, Hund’s rules come into play. Hund’s first rule states that orbitals of equal energy levels are occupied by the same electron (which spins in the same direction), and it is denoted by arrows going up and down ( ↑ ↓ ). Therefore, since the atom has 16 electrons, it will look like this: ( ↑ ↓ ) ( ↑ ↓ ) ( ↑ ↓ ↑ ↓ ↑ ↓ ) ( ↑ ↓ ) ( ↑ ↓ ↑ ↓ _ _). Hund’s second rule states that electrons within the same orbital spin in opposite directions, which is seen in the above element since the last two electrons face opposite directions. Given that the last electron is spinning upwards, the spin quantum number is ms = -1/2.