Atomic Structure & Periodic Trends

Question 1

What is the Molarity (M) formula?

Answer 1

moles of solute/liters of solution = mol/L

Question 2

What is the molality (m) formula?

Answer 2

moles of solute/kilograms of solvent = mol/kg

Question 3

What is electronegativity?

Answer 3

the tendency for an atom to attract a bonding pair of electrons. Electronegativity unlike other periodic trends is measured within a bond.

Question 4

What does Z_eff stand for?

Answer 4

Effective nuclear charge

Zeff is the net positive charge pulling these electrons towards the nucleus. The stronger the pull on the outermost electrons (valence electrons) towards the nucleus, the higher the effective nuclear charge.

Question 5

What is the effect of Z_eff on periodic trends?

What does higher Zeff correlate with on the periodic table?

Answer 5

The greater the effective nuclear charge the greater the electronegativity

Effective nuclear charge depends on the number of protons in the nucleus, the distance from the nucleus, and the amount of shielding by inner shell electrons. The number of protons increases Zeff​ , while the distance and amount of shielding decreases Zeff​

Question 6

True or False: Zeff depends on the attraction of the bonding pair towards the nucleus

Answer 6

False

Effective nuclear charge depends on the number of protons in the nucleus, the distance from the nucleus, and the amount of shielding by inner shell electrons. The number of protons increases Zeff​ , while the distance and amount of shielding decreases Zeff​

Question 7

The atomic number is represented by the letter…

Answer 7

Z

the # of protons = Z

Question 8

The mass number is represented by the letter…

Answer 8

A

the # of protons + neutrons = A

Question 9

Group 1 of the periodic table is…

Answer 9

alkali metals

Question 10

What are characteristics of alkali metals?

Answer 10

• distinctive flame colors
• good electrical conductors
• solid under standard conditions
• shiny or lustrous
• ductile (can be easily stretched into wires)
• malleable (can be made into shapes/sheets)
• very reactive!

mercury is the exception to the solidity characteristic

alkali metals have lone valence electrons making them incredibly reactive

Question 11

Group 2 of the periodic table

Answer 11

Alkaline earth metals

Question 12

What are characteristics of alkaline earth metals?

Answer 12

• metallic character
• reactive
• good conductors
• oxidation state of 2+

they also form hydroxides when they react with water

Question 13

What are characteristics of transition metals?

Answer 13

• lusterous
• hard & durable
• good conductors
• take on vivid colors due to electronic transitions between D orbitals
• multiple oxidation states

characterized by many oxidation states due to the low reactivity of the unpaired d electrons

Question 14

What are characteristics of non-metals?

Answer 14

• not shiny/lustrous
• poor conductors

Question 15

What are the characteristics of metalloids

also known as semimetals

Answer 15

they share the characteristics of metals and non-metals
* brittle
* poor to decent conductors
* act like nonmetals in chemical reactions, but can vary

Boron and Silicon are the ones you will most likely see on the MCAT

Question 16

Chalcogens are

what group #? What elements?

Answer 16

Group 16, include oxygen and sulfur

have nearly filled valence shells

Question 17

What is group 17 of the periodic table?

Answer 17

Halogens

F, Cl, Br, I

have nearly filled valence shells and are very reactive, especially with alkali metals

Question 18

What is the effect of Z_eff on periodic trends?

What does higher Zeff correlate with on the periodic table?

Answer 18

The greater the effective nuclear charge the greater the electronegativity

Effective nuclear charge depends on the number of protons in the nucleus, the distance from the nucleus, and the amount of shielding by inner shell electrons. The number of protons increases Zeff​ , while the distance and amount of shielding decreases Zeff​

Question 19

Describe the relationship between transition metals and ionization energy

Answer 19

transition metals have little variability in their ionization energies and electronegativities due to their similar valence electron shells, which is the s shell

Question 20

What is the relationship between reactivity and oxidation states

Answer 20

High reactivity would limits the number of oxidation states

Question 21

The amount of energy required to remove an electron from an isolated atom or molecule is….

Answer 21

ionization energy

Question 22

the energy change that results from adding an electron to a gaseous atom

Answer 22

electron affinity

Question 23

What periodic aligns with the radius of an atom decreasing from left to right across a period as more protons and electrons are added?

Answer 23

atomic radius (also called atomic size)

Question 24

______, _____ and _____ periodic trends increase diagonally from bottom left to top right

Answer 24

Ionization energy, electron affinity, and electronegativity

Question 25

E = hf represents ... | What does each variable stand for? What does the equation quantify?

Answer 25

Electromagnetic radiation ## Footnote E = energy of electromagnetic radiation h = Plank's constant f = frequency of light

Question 26

What are the units of the frequency of light (*f*) ?

Answer 26

3.00 x 10⁸ m/s

Question 27

# True or False Electromagnetic radiation includes the full continuum of light

Answer 27

True! | This radiation encapsulates full continuum of wavelengths ## Footnote Think of everything from visible light to gamma waves to X-rays!

Question 28

E = hc/ƛ represents.... | What does it quantify? What do the variables represent?

Answer 28

The energy of a **photon** ## Footnote This equation is equal to the electromagnetic radiation formula E=hf !

Question 29

# True or false Each element has an absorption and emission sprectrum

Answer 29

True! ## Footnote Since energy is aborrbed and released in quanta, the absorption or emission of electromagnetic radiation results in a caracteristic absorption and emission spectrum that are unique for each element

Question 30

# Name the equation | What does it represent?

Answer 30

The Rydberg formula ## Footnote Used to predict the wavelength of light resulting from an electron moving between energy levels of an atom

Question 31

# What does this equation represent? Eqn 4. pg. 6 NS

Answer 31

Energy change (in Joules) of an electron moving between energy levels | Modified Rydberg equation

Question 32

(+) ΔE means that energy is ____ and - ΔE means that energy is _____

Answer 32

absorbed, released

Question 33

# Define the term Posits that we cannot simultaneously know the exact position *and* the momentum of a given electron

Answer 33

Heisenberg uncertainty principle

Question 34

Denotes the energy level of an electron | Corresponds to the Bohr radii ## Footnote Hint: represented by *n*

Answer 34

principle quantum number ## Footnote the higher the n value, the greater the energy, and thus the further the distance from the nucleus

Question 35

The periodic table is arranged in rows corresponding to...

Answer 35

Bohr radii; n ## Footnote i.e Sodium is in the 3rd period, and this element has a principal quantum number of n=3

Question 36

What quantum number describes the shape of an orbital's subshell? | Give the letter and the name

Answer 36

angular momentum quantum number (*l*) | azithmul quantum number ## Footnote note: there is 1 s orbital, 3 p orbitals, 5 d orbitals, and 7 f orbitals

Question 37

Which quantum number describes the spatial orientation of the orbital region of space with respect to an applied magnetic field?

Answer 37

magnetic quantum number m_l ## Footnote described in integers of -l to +l

Question 38

What quantum number describes the spin orientation of the electron in an external magnetic field?

Answer 38

spin quantum number m_s ## Footnote the two spin orientations are m_s = +1/2 (up) or -1/2 (down). Note that because of spin orientations, an s orbital can have up to 2 electrons, p orbitals 6 electrons, d can have 10, and f can have 14

Question 39

# Name the principle/rule: every orbital in a sublevel is singly occupied before any orbital is doubly occupied

Answer 39

Hund's rule

Question 40

# Name the principle/rule: electrons are filled into atomic orbitals in the increasing order of orbital energy level

Answer 40

Aufbau principle

Question 41

# Name the principle/rule: No two electrons can have the same quantum numbers

Answer 41

Pauli exclusion principle