Chemistry 65.100 A, V
Midterm Test #1
October 13, 2000

A periodic table is on the back of this sheet!

Part A. Answer each question with a few sentences or equations where necessary. (5 Marks each)

1. State the Pauli Exclusion Principle.
2. Write down de Broglie's equation, define each term, and briefly explain the significance of the equation.
3. State how many valence electrons each of the following atoms have: Li, V, Ga, I, Rn.
4. The electronic configuration of Silver (Ag) is [Kr]5s¹4d¹⁰. Why is it not [Kr]5s²4d⁹ (which would be predicted from the orbital filling order)?
5. How and why does ionization potential change going left to right across a period?
6. Why does LiCl_(s) have a larger lattice energy than KCl_(s)?

1. Lines in the Lyman series of the hydrogen spectrum come from transitions to the m = 1 shell from higher shells.

(a) Calculate the wavelength (in nm) of the highest energy transition in this series.
(b) Calculate the energy of the resulting photons in kJ/mol.
(c) In what portion of the electromagnetic spectrum are these photons (UV, Visible or IR)?

2. Uranium metal (U) can be produced by the reduction of the fluoride by magnesium metal according to the reaction:

UF_4(s) + 2 Mg_(s) à U_(s) + 2 MgF_2(s)

Calculate how many kilograms of U_(s) can be obtained from 1000 kg of UF_4(s) with an excess of magnesium.

3. Predict the formulas of the compounds formed by reacting:

(a) Mg with S
(b) Sc with O
(c) Ti with N
(d) Ba with Br
(e) H with P

Some Useful Constants

N_av = 6.02 x 10²³ mol^-1
h = 6.63 x 10^-34 J s
c = 3.00 x 10⁸ m s^-1
R = 0.01097 nm^-1