Electromagnetic Spectrum
Say a mnemonic that you will use to help you remember the electromagnetic spectrum. Name the trends regarding frequency, energy, and wavelength with the corresponding mnemonic.
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R -> G
Wavelength decreases
Energy increases
Frequency increases
What are the 4 quantum numbers? How do you determine them?
n, row number
l, 0 thru n-1
ml, every zero, and every positive/negative l value
ms, determined thru orbital diagram
What do the s,p,d,f blocks represent? What are their shapes?
They represent orbitals.
s - circle
p - looks like 8
d - looks like two 8s put together
f - looks like three 8s put together
What is effective nuclear charge?
The amount of positive charge experienced by any individual electron. (Essentially more protons = higher ENC)
Which has the highest energy, highest frequency, and longest wavelength in the visible light spectrum?
Highest energy: violet light
Highest frequency: violet light
Longest wavelength: red light
What is n value of barium?
6
What is the full electron configuration of carbon? Which orbital is paramagnetic?
1s2 2s2 2p2
p block is paramagnetic
Which ions are isoelectronic: Ca+, K-, Cl2-, P4-, S3+
Ca+, Cl2-, P4-
The wavelength of the sodium D line is 589 nm. What are the frequency and the energy for this line?
𝑐=𝜆𝑣→ 𝑣=𝑐/𝜆= (3∗108 𝑚/𝑠) / (589 ∗10-9 m)
𝑣 = 5.09*1014 Hz
𝐸=ℎ𝑣=(6.63∗10-34 𝐽∗𝑠)*(5.09*1014 Hz)
𝐸=3.38*10-19 J
What are l values of calcium?
0, 1, 2, 3
Write the noble gas electron configuration of Einsteinium? Is the orbital diagram diamagnetic or paramagnetic?
[Rn] 7s2 5f10
s block is diamagnetic
f block is paramagnetic
What element has the largest atomic radius? Explain how atomic radius trends vary down a group and across a period. Explain why the trend is like this.
Francium
Atomic radius decreases as you move left to right on the periodic table due to the increasing effective nuclear charge, which increases the attraction to the electrons- pulling the electron cloud closer to the center.
Atomic radius increases down the groups because the number of energy levels (n) increases, which increases the distance from the center to the outermost energy level, thereby increasing the atomic radius.
A line in the spectrum of an element was observed to have a frequency of 5.16∗1015 𝑠−1. What is the wavelength of the radiation? (*Remember sig figs).
𝑐=𝜆𝑣 → 𝜆=𝑐/𝑣=(3∗108𝑚/𝑠) / (5.16∗1015 s^-1) = 5.80∗10-8 𝑚
What are ml values of nitrogen?
-1, 0, 1
Write the noble gas configuration of Au. Is the orbital diagram paramagnetic or diamagnetic?
[Xe] 6s1 4f14 5d10
d and f blocks are diamagnetic
s block is paramagnetic
What element has the largest ionization energy? Explain how atomic radius trends vary down a group and across a period. Explain why the trend is like this.
Helium
Effective nuclear charge increases as you go left to right on the periodic table due to the increasing effective nuclear charge. As the attraction pulls the electron cloud closer to the center, more energy is required to remove an electron. The ionization energy decreases as you move down a group because the number of energy levels (n) increase, causing there to be a greater distance from the nucleus and highest energy electron. The increased distance weakens the attraction, meaning less energy is needed to remove an electron.
If the energy of a light wave is 7.5∗10-20 𝐽, what is the wavelength of the radiation? (*Remember sig figs)
𝐸=ℎ𝑣→𝑣=𝐸/ℎ=(7.5∗10-20 𝐽) / (6.63∗10-34 𝐽∗𝑠)
v =1.1312 *1014 Hz
𝑐=𝜆𝑣→ 𝜆=𝑐/𝑣= (3∗108 𝑚/𝑠) / (1.1312 ∗1014 s-1)
𝜆 = 2.7*10-6 m
What are the possible values for the spin number, ms?
+1/2, -1/2
Write the noble gas configuration of Fe3+. Is the orbital diagram paramagnetic or diamagnetic?
[Ar] 3d5
d block is paramagnetic
Organize the following isoelectronic ions by increasing atomic radius: Se, Br+, As-, Ge2-
Br+ < Se < As- < Ge2-