Name:
Date:
Period:
Unit 3 Study Guide
EM Spectrum, Electron Configurations, Periodic Trends
Electrons absorb energy
to jump energy levels.
EM Spectrum
By using the Bohr model of a Hydrogen atom to the left, answer the following
questions.
1. Light (photons) will be given off by an atom when the electrons fall back to
the ______ground____ _ state.
2. For an electron to move from the ground state to the excited state energy
must be
absorbed
.
Look at the model of a wave of light to answer the question 3 and 4.
Electrons release energy as light or
photons when they fall back down
to their ground state.
3. What is a bundle or packet of energy in a light wave called? A photon
4. What 2 characteristics does electromagnetic radiation have that describes
how it moves through space? (Think about the wave machine.)
wavelength and frequency
5. Write the term that each of the following symbols stand for
& include the proper units:
(1 meter = 1 x 109 nm) (1 MHz = 1 x 106 Hz)
Wavelength of light
Photons – Bundles of
energy in a wave of light.
E = energy (J)
ν =frequency (Hz or 1/s)
λ = wavelength (m)
c = speed of light (m)
h = Planck’s constant (J s)
6. Write the equation for the speed of light. c = λν
6. Write the equation for the speed of light.
7. What is the value for the speed of light (c)? (Remember: All light travels at the same speed)!
3.00 x 10 8 m/s
8. Write the equation for the energy of a wave of light.
E = hν
9. What is the value for Plank’s constant (h)?
6.626 x 10-34 J s
Solve the following EM wave problems using the information you found above.
10. In the emission spectrum of Argon, there is a green band with a wavelength of 5.55 x 10-7 m. What is the energy of
the wave?
3.00 x 10 8 m/s = 5.55 x 10 -7m (ν)
ν = 5.41 x 1014 1/s
E = (6.626 x 10-34 Js)( 5.41 x 1014 1/s)
__3.58 x 10-19 J_
11. What is the wavelength of a wave with a frequency of 120.8 MHz?
120.8 MHz x ______1MHz____ = 1.208 x 10 -4 Hz
1 x 106 Hz
8
3.00 x 10 m/s = (x)( 1.208 x 104 Hz)
x = 2.48 x 1012 m
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Date:
Period:
12. A spectral line with 7.75 x 10-19 J of energy is produced when electrons of sodium release energy. What is the
frequency of this photon?
7.75 x 10-19 J = (6.626 x 10-34 Js)( x )
X = 1.17 x 1015 1/s
13. A photon has a wavelength of 4.40 x 10-7 m. What is the color of the photon? blue
Electron Configurations
14. Fill in on the blank P.T where the s blue, p red, d green, and f yellow
orbitals are represented.
15. How many energy levels of electrons are there? (How many rows are there on the P.T?) __7______
16. How many types of orbitals are there?
4
17. How many electrons can each of the orbitals hold? s = 2
p=6
d = 10
f = 14
18. Draw the shape of each type of orbital
underneath the letter.
19. How many electrons can energy level 2 hold? (How many total electrons are in energy level 2?)
8
20. Write the electron configuration for the following elements. (You may use the short hand electron configuration).
a) K 1s22s23s23p64s1
b) Rb 1s22s23s23p64s23d104p65s1
c) Ag 1s22s23s23p64s23d104p65s24d9
d) S 1s22s23s23p4
e) As 1s22s23s23p64s23d104p3
f) Sc 1s22s23s23p64s23d1
21. Identify the element from the given electron configuration.
a. 1s22s22p63s23p2 ____Si
b. [Ar]4s23d104p3 ___ As
c. [Kr] 5s24d105p2 Sn
Periodic Table Trends
Consider the elements Nitrogen (N), Potassium (K), Bromine (Br), and Fluorine (F).
b)
c)
d)
e)
f)
a. Fe2+
Which element has the highest electronegativity? ______F____________
Which element has the smallest ionization energy? _____K_____________
Which element has the largest atomic radius? _________K____________
Will sodium be smaller or larger when it ionizes? ___smaller_______________
Circle the ion or element in the given pair that has the largest radius.
Fe
b. N N-3
c. As As-3
26. Write each of the three elements in order from SMALLEST to LARGEST electronegativity.
a. lithium, potassium, sodium K Na Li
d. Ca
Ca2+