Parts of the EM Spectrum
What are three types of waves on the EM spectrum with wavelengths less than visible light?
UV, X rays, Gamma rays
How many sublevels are there per energy level?
Same as the number of the energy level
1st energy level = 1 sublevel (s)
3rd energy level = 3 sublevels (s,p,d)
What is the formula relating the wavelength and frequency of electromagnetic radiation?
s = λ·f
What is the formula used to calculate the energy of a photon?
E = hf
What is the complete electron configuration for Cr, Chromium?
1s22s22p63s23p64s23d4
What are the approximate wavelengths (in nm) for blue and red visible light?
Blue ~ 450 nm
Red ~ 710 nm
How many total electrons can be in each of the following energy levels?
a.) 1st energy level
b.) 5th energy level
1st = 2n2 = 2(1)2 = 2
5th = 2n2 = 2(5)2 = 50
The frequency of the radiation used in microwave ovens is 2.45 GHz. What is the wavelength of this radiation in m?
0.122 m
What are the mathematical relationships (inverse or direct) between:
a.) wavelength and energy
b.) frequency and energy
a.) inverse- as wavelength decreases, energy increases
b.) direct - as frequency increases, energy increases
Which of the following ions would NOT have the same electron configuration as Ar?
Cl-1 Ca+2 Sc+3 P-2
P-2
Place the following types of radiation in order of increasing energy per photon:
a.) radar signals
b.) x ray
c.) gamma rays from nuclear reaction
d.) red light from neon sign
e.) UV radiation from tanning bed
a,d,e,b,c
1. What are the shapes of the s and p orbitals?
2. How many electrons can fit into an orbital?
1. s = spherical p = dumbell
2. 2 electrons fit into each orbital
The US Navy has a system of communicating with submarines. The system uses waves with a frequency of 76 Hz. What is the wavelength of this radiation in meters?
3.95 x 106 m = radio waves
Violet light has a wavelength of 410 nm. Calculate the energy of 1.0 mole of violet light in J.
290,000 J
What is the noble gas electron configuration for Mo?
[Kr] 5s24d4
Select the radiation with the shorter wavelength from each pair.
1. red light vs. green light
2. IR vs. UV
3. X ray vs. microwave
4. green light vs. UV
1. green light
2. UV
3. X ray
4. UV
Name the letters that represent the sublevels in each energy level. Give the number of orbitals in each sublevel.
s = 1 orbital
p = 3 orbitals
d = 5 orbitals
f = 7 orbitals
1. wavelength
2. frequency
3. period
4. amplitude
1. wavelength: distance from crest to crest of a wave (nm)
2. frequency: number of waves that pass a point in a given time period (Hz)
3. period: time for one wave to pass (s)
4. amplitude: maximum height of a wave (nm)
Your eyes receive a signal consisting of blue light with a λ = 470 nm. What is the energy of 1 photon of this light?
2.90 x 10-14 J
Answer the questions referring to the following electron configuration: [Ar]4s23d7
a.) what is the identify of the element?
b.) is it paramagnetic or diamagnetic?
c.) how many unpaired electrons does it have?
a. Cobalt
b. paramagnetic
c. 3
Name the 7 parts of the EM spectrum from long wavelength to short wavelength.
Give the approximate range in wavelengths. (in m)
Give the approximate range in frequency (in Hz)
Radio-Microwave-IR - Visible - UV-Xrays-Gamma
101 m - 10-13 m
101 Hz - 1026 Hz
Answer each of the following questions:
1. How many sublevels are in the 3rd energy level?
2. How many electrons can a 4f orbital hold?
3. How many total electrons can the 6th energy level hold?
4. How many orbitals are in the 4th energy level?
1. 3
2. 2
3. 72
4. 16
Calculate the wavelength, in nm, of radiation with a frequency of 4.37 x 1014 Hz.
What region of the electromagnetic spectrum is this radiation in?
687 nm - visible light (red)
By what factor are X rays (λ= 10-10 m) more energetic than microwaves (λ= 1010 m)?
1020 x
Write the noble gas electron configuration for a Fe+3 ion.
[Ar] 3d5