Chapter 9 - Electrons in Atoms and the Periodic Table

Question 1

Electromagnetic Radiation

Answer 1

a type of energy that travels through space at a constant speed of 3.0 x 10^8 m/s

Question 2

Wavelength

Answer 2

the distance bw adjacent wave crest

• for visible light, wavelength determines color
• the shorter the wavelength, the greater the energy

Question 3

Red light

Answer 3

longest visible wavelength

750nm

Question 4

Violet light

Answer 4

shortest visible wavelength

400nm

Question 5

Photon

Answer 5

particle of light
a single packet of light energy
-the shorter the wavelength, the greater the energy in photons
ex) violet has a short wavelength and carries more energy per photon

Question 6

Speed of Light

Answer 6

3.0 x 10^8 m/s

Question 7

Electromagnetic Spectrum

Answer 7

entire range of electromagnetic radiation from 10^5 m (low energy) to 10^-15 m (high energy)

-visible light is minute(~10^-6.5)

Question 8

Gamma Ray

Answer 8

shortest wavelength

• produced by sun and stars
• damages visible molecules

Question 9

X-Rays

Answer 9

pass thru substances that block visible light

• short wavelength
• damages visible molecules

Question 10

UltraViolet UV light

Answer 10

component of sunlight that produces sunburn or suntan

-damages visible molecules

Question 11

Visible light

Answer 11

ranges from violet to red

-photons do not damage biological molecules

Question 12

Infrared Light

Answer 12

• the heat we feel when we place a hand near a hot object is infrared light
• night vision goggles show the infrared light

Question 13

Microwaves

Answer 13

• used for radars and microwave ovens

- efficiently absorbed by water

Question 14

Radio Waves

Answer 14

the longest wavelength used to transmit signals used by AM, FM radio, cell phones, tv

Question 15

Wavelength vs. Frequency vs. Photon

Answer 15

inverse relationship.

High wavelength=Low frequency=Low energy per photon

Question 16

Emission Spectrum

Answer 16

the result of separating light emitted by an individual element

Question 17

Bohr Model

Answer 17

• electrons travel around the nucleus in circular orbits at specific fixed distances fr the nucleus (not bw orbits)
• the energy of each Bohr Orbit is quantized and specified by a quantum number
• energy of each orbit increases w/increasing quantum no.

Question 18

Quantum Number

Answer 18

n: 1,2,3,…

- energy of each orbit increases w/increasing N

Question 19

Excitation/Relaxation of Electrons

Answer 19

• when energy is put into an atom, electrons are excited into higher-energy orbits
• when an electron relaxes from higher orbits into lower-energy orbits, the atom emits light
• the energy + wavelength of the emitted light corresponds to the energy difference bw the two orbits in the transition
• since the energy is fixed + discrete, the emitted light is also fixed+ discrete

Question 20

Quantum-Mechanical Model

Answer 20

Bohr orbits are replaced with quantum-mechanical ORBITALS

-electron’s path is unpredictable

Question 21

Orbitals

Answer 21

represents probability maps that show a statistical distribution of where the electron is likely to be found

• not an exact path an electron takes
• represented by a number + a letter
• vs orbit which was a circular path + represented by a number

Question 22

Principal Quantum Number (n)

Answer 22

specifies the principal shell of the orbital
-the higher the principal quantum number, the higher the energy of the orbital
n= 1,2,3,…

Question 23

Subshells (s, p, d, f)

Answer 23

the number of subshells in a given principal shell is equal to the value of n

ex) n= shell 2 = 2 subshells
- the letter indicates the subshell of the orbital and specifies the shape

Question 24

2s orbital

Answer 24

spherical shape

- higher in energy and larger than 1s orbital

Question 25

Ground State

Answer 25

lowest energy state

Question 26

2p subshell

Answer 26

contains 3 2p orbitals | -dumbbell shape but each at different orientations

Question 27

3s and 3p subshell

Answer 27

contains 3 subshells (s, p, d) | -3s + 3p orbitals are similar to 2s + 2p orbitals but slightly larger and higher in energy

Question 28

3d subshell

Answer 28

- contains 5 d orbitals | - looks like 4 leaf clovers of different orientations and one dumbbell surrounded by a donut

Question 29

4s, 4p, 4d subshell

Answer 29

similar to 3s, 3p, 3d orbitals but slightly larger and higher energy

Question 30

4f subshells

Answer 30

contains 7 orbitals

Question 31

1 subshell

Answer 31

has a single spherical orbital

Question 32

Excited State

Answer 32

when an electron is in a higher energy orbital, they are in an excited state - unstable and will usually fall/relax back to lower energy orbitals - relaxing into lower energy orbitals emit light

Question 33

Electron Configuration

Answer 33

illustrates the occupation of the orbitals by electrons for a particular atom

Question 34

Pauli Exclusion Princicple

Answer 34

orbitals may hold no more than 2 electrons with opposing spins

Question 35

Hund's Rule

Answer 35

when filling orbitals of equal energy, electrons fill them singly first w parallel spins

Question 36

[Noble Gas]

Answer 36

when writing an electron configuration beyond a noble gas, it can be shortened by replacing a portion with the noble gas sign with brackets ex) [Ne] = 1s2 2s2 2p6 Na: [Ne]3s1

Question 37

Electron configuration order

Answer 37

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s

Question 38

Electron configuration order

Answer 38

``` 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f ```

Question 39

Valence Electrons

Answer 39

electrons in the outermost principal shell -the group number (such as 1A-8A) tells how many valence electrons there are Si 1s2 2s2 2p6...3s2 3p2 ......"core e"........."valence e" 2+2=4 valence e. Si is in group 4A

Question 40

Outermost principal shell

Answer 40

the principal shell with the highest principal quantum number (n) - involved in chemical bonding - electrons are held more loosely and are most easily lost or shared

Question 41

Core Electrons

Answer 41

all electrons NOT in the outermost principal shell ex) Si 1s2 2s2 2p6...3s2 3p2 ......"core e"........."valence e"

Question 42

s-block elements

Answer 42

Groups 1A, 2A, and Helium

Question 43

p-block elements

Answer 43

Groups 3A-8A | except He

Question 44

d-block elements

Answer 44

Groups 3B-8B, 1B-2B (transition metal) principal quantum number of d shells are (n-1) ex) Cu is in row 4, but has 3d^10

Question 45

f-block elements

Answer 45

The separate portion of the transition metals

Question 46

writing an electron configuration based on the periodic table

Answer 46

- core/inner e- configuration is replaced w [noble g] - row # = highest principal # - elements w d shells, the d# = row#-1

Question 47

Ionization Energy

Answer 47

- the energy required to remove an e- from the atom in the gaseous state - as you move across the periodic table from left to right, ion.energy INCREASES - as you move down (top to bottom) the periodic table, ion.energy DECREASES Na + (ionization energy) ->Na+ +e-

Question 48

atomic size on the periodic table

Answer 48

- as you move across the periodic table from left to right, atomic size DECREASES - as you move down (top to bottom) the periodic table, atomic size INCREASES

Question 49

Metallic Character

Answer 49

- as we move across the periodic table, the metallic character decreases - as we move down a column, metallic character increases