Wavelength, Energy, Frequency
Light
Electron Configuration/Quantum Numbers
Moles/Empirical Formula
Periodic Trends
100
What is the frequency, in Hz, associated with a wavelength of 3.7m?
8.1 x 107 Hz
100
What is the relationship between wavelength and energy?
Inverse relationship
100
What do n, l, ml and ms stand for in terms of quantum numbers?
n = principal quantum number
l = angular quantum number
ml = magnetic quantum number
ms = spin quantum number
100
How many particles are in 1.50 moles of CO₂?
9.03×1023 molecules CO₂
100
What is the atomic trend of each:
Atomic Size
Ionization Energy
Electron Affinity
Atomic Size: Increases down and decreases across
Ionization Energy: Decreases down and increases across
Electron Affinity:Decreases down and increases across
200
What is the wavelength, in nm, of a frequency of 375 Hz?
8 x 1014 nm
200
Draw/List the electromagnetic spectrum
200
Give all possible quantum number sets for electrons in the 2p subshell.
(2,1,−1,±1/2),(2,1,0,±1/2),(2,1,+1,±1/2)
200
How many grams of calcium are required to produce 5.00 moles of calcium chloride (CaCl₂)?
203.9 g
200
Arrange the following elements in increasing ionization energy:
Na, Cl, S, Mg
Na < Mg < S < Cl
300
What is the frequency, in s-1, associated with a wavelength of 227 nm?
1.32 s-1
300
Is an electron going from n=1 to n=3 an emission or an absorption? Explain in terms of energy.
Absorption. Electrons are gaining energy, so energy must be taken in from the surroundings, meaning it is absorbed.
300
How many unpaired electrons are in nitrogen (N)?
1s22s22p3 → 3 unpaired
300
A compound is 70% iron and 30% oxygen by mass. What is its empirical formula?
Fe₂O₃
300
Rank the following ions by increasing ionic radius, and explain your reasoning:
O²⁻, F⁻, Na⁺, Mg²⁺, and Al³⁺
O²⁻ > F⁻ > Na⁺ > Mg²⁺ > Al³⁺.
400
What is the wavelength, in m, associated with an energy of 8.7 J?
2.3 x 10-26
400
The wave property of light allows for what?
Diffraction and constructive interferenace
400
Can two electrons in the same atom have identical three quantum numbers but opposite spins? Explain using the Pauli Exclusion Principle.
Yes. Two electrons can share n,l, and ml (same orbital) only if ms differs; Pauli forbids all four being identical.
400
If 10.0 g of aluminum reacts with excess oxygen, how many moles of Al₂O₃ will form?
0.185 mol
400
Why does fluorine have a higher electron affinity than oxygen, even though both are in the same period?
Both want to complete their p orbitals, but F has a higher nuclear charge.
F’s smaller size → incoming electron feels a stronger attraction.
500
What is the wavelength, in nm, of a frequency of 865 GHz?
3.46 x 105 nm
500
Would there be a larger wavelength of light associated with an electron going from n=5 to n=3 or n=2 to n=1?
Electron going from n=5 to n=3
500
What is the expected electron configuration for the Fe²⁺ ion, and why does it differ from the neutral atom?
[Ar]3d6
Reason: When an atom forms a positive ion, electrons are always removed from the orbital with the highest principal quantum number first, as these are the outermost electrons and thus the most exposed to the influence of the nucleus. For iron, the 4s orbital has a higher principal quantum number than the 3d orbital.
500
A hydrocarbon sample contains 85.7% carbon and 14.3% hydrogen. When burned, 0.100 moles of it produce 0.400 moles of CO₂. Determine the empirical formula.
CH₂
500
Why do ionization energy and electron affinity decrease down the periodic table and increase across it?
Ionization energy - The more protons in the nucleus, as you go across, the stronger the attraction of the nucleus to electrons. Makes it harder to remove electrons.
Electron Affinity: Elements are more likely to want to gain an electron to fill out their shells as we go across, so the energy change from that transfer would be higher.