Ch 5

Question 1

Periodic Law of the Elements

Answer 1

when elements are arranged in a particular order (increasing atomic number), elements of similar properties occur at periodic intervals

Question 2

The Theoretical basis for the periodic law lies in

Answer 2

electronic theory

Question 3

A new set of physical laws were needed to explain what experiments were revealing about atoms and light

Answer 3

• These laws predicted quantized (non-continuous) behavior
• These laws lead to strange predictions of behavior that is impossible to picture, but explains countless experiments
• Our objective is to understand how electrons behave in the atom

Question 4

The energy of an electron in an atom is quantized

Answer 4

it exists only in certain fixed quantities, rather than being continuous

Question 5

It is physically impossible to determine a quantum particle’s

Answer 5

position and momentum

Question 6

Light

Answer 6

• is a form of electromagnetic radiation
• travels as waves at a constant speed
• carries radiant energy through completely empty space

Question 7

All waves have:

Answer 7

Wavelength and Frequency

Question 8

Wavelength

Answer 8

horizontal distance between two corresponding points on a wave (units are usually m)

Question 9

Frequency

Answer 9

the number of complete wavelengths that pass a stationary point in a second (units are usually Hz, s-1)

Question 10

Light is a stream of small particles called photons that have

Answer 10

Energy related to their frequency.

Question 11

The electromagnetic spectrum

Answer 11

• Arranges forms of energy from lower to higher
• Arranges energy from longer to shorter wavelengths
• Shows visible light with wavelengths from 700-400 nm

Question 12

All electromagnetic radiation moves through a vacuum at a specific speed.

Answer 12

c = 3.00 x 10^8 m/s

Question 13

White light that passes

through a prism

Answer 13

• Is separated into all colors called a continuous spectrum

* Gives the colors of a rainbow

Question 14

An atomic spectrum consists of lines

Answer 14

Of different colors formed when light from a heated element containing an element passes through a prism

Question 15

When gases are heated, they give off light at certain frequencies

Answer 15

In other words, atoms absorb or emit energy only at specific wavelengths (specific energies)

Question 16

Bohr’s Model of the Atom

Answer 16

• His goal was to create a model that would explain the atomic spectrum of Hydrogen
• Postulates that there are only certain positions about the nucleus an electron can reside – certain “allowed orbitals.”

Question 17

When electrons absorb energy (in the form of light),

Answer 17

they move from a lower energy level to a higher one.

Question 18

When electrons move from a higher energy level to a lower energy level

Answer 18

they give off energy in the form of light (“emission”)

Question 19

Electrons are arranged in

specific energy levels that

Answer 19

• Are labeled n = 1, n = 2, n = 3, and so on
• Increase in energy as n increases
• Have the electrons with the lowest energy in the first energy level (n=1) closest to the nucleus

Question 20

Energy Level Changes

Answer 20

• An electron absorbs energy to “jump” to a higher energy level.
• When an electron falls to a lower energy level, energy is emitted.
• In the visible range, the emitted energy appears as a color.

Question 21

Sublevels

Answer 21

• The s sublevel has the lowest energy within that sublevel.

* The s sublevel is followed by the p, d, and f sublevels in order of increasing energy.

Question 22

An orbital

Answer 22

• Is a three-dimensional space around a nucleus where an electron is found most of the time.
• Has a shape that represents electron density (not a path the electron follows).
• Can hold up to 2 electrons.
• Contains two electrons that must spin in opposite directions.

Question 23

There are a different number of orbitals for each subshell type

Answer 23

• In an s subshell, there is 1 orbital
• In a p subshell, there are 3 orbitals
• In a d subshell, there are 5 orbitals
• In a f subshell, there are 7 orbitals.

Question 24

An s orbital

Answer 24

• Has a spherical shape around the nucleus.
• Increases in size around the nucleus as the energy level n value increases.
• Is a single orbital found in each s sublevel.

Question 25

A p orbital

Answer 25

• Has a two-lobed shape .
• Is one of three p orbitals that make up each p sublevel.
• Increases in size as the value of n increases.

Question 26

Each sublevel consists of a specific number of orbitals

Answer 26

An s sublevel contains one s orbital.

• A p sublevel contains three p orbitals.
• A d sublevel contains five d orbitals.

*An f sublevel contains seven f orbitals

Question 27

Three things distinguish all electrons:

Answer 27

• Principle quantum number
• Type of orbital (s, p, d, f)
• Spin (up, down)

Question 28

Energy levels fill with electrons

Answer 28

• In order of increasing energy.
• Beginning with quantum number n = 1.
• Beginning with s followed by p, d, and f.

Question 29

tells us in which shells & subshells the electrons for an element are located.

Answer 29

Electron configurations

Question 30

Electron configurations -> Rules:

Answer 30

1. Electrons fill orbitals starting with lowest energy first
2. There can be no more than 2 electrons in any orbital, and those electrons must have different spins
3. For orbitals in the same subshell, electrons fill each orbital singly before any orbital gets a second electron

Question 31

An abbreviated (noble gas shorthand) configuration shows

Answer 31

• The symbol of the noble gas in brackets that represents completed sublevels
• The remaining electrons in order of their sublevels

Question 32

Visual Representations of Electron Configurations

Answer 32

• Each line (or circle) represents an orbital
• Each arrow represents an electron
• The rules of electron configurations are followed

Question 33

Box Diagrams -> Remember:

Answer 33

Electons fill orbitals of equal energy first before they doubly occupy an orbital

Question 34

The Maximum Number of Electrons any single orbital can hold is

Answer 34

2

Question 35

Electrons are distinguished from each other an arrow convention

Answer 35

one must be up, one must be down if electrons are in the same orbital

Question 36

Elements that similar properties have the same number of

Answer 36

valence electrons

Question 37

Valence Electrons

Answer 37

For elements in the “s” and “p” block - valence electrons are the electrons in the outer-most electron shell (the shell with the highest n value)

Question 38

The distance from the nucleus to the valence electrons

Answer 38

Atomic radius

Question 39

Atomic radius

Answer 39

• increases going down each group of representative elements.
• decreases from left to right across a period because more protons increase nuclear attraction for valence electrons.

Question 40

An electron-dot symbol

Answer 40

Shows the valence electrons around the symbol of the element.