Rubidium has an electronic configuration of 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s. Which of the following properties would you expect it to have?

1. relatively large
2. chemically active
3. inert
4. low electron binding energy
5. easily ionized

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Quartz (SiO₂) is a covalent solid. Which of the following properties which you expect it to have?

1. It is good electrical conductor.
2. It is soft because it has a low cohesive energy.
3. It is transparent.
4. It has a high melting point.
5. It has high thermal conductivity.

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Scandium is a metal. What would you expect to be true of it?

1. It is a good conductor.
2. It is transparent.
3. It is held together with ionic bonds.
4. Its valence electrons are shared by all of the atoms in the metal.

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Lithium fluoride is a material with ionic bonds. What would you expect to be true of this material?

1. It is a good conductor.
2. It is transparent.
3. It readily conducts heat.
4. It has a high cohesive energy.

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Germanium (Ge) is in the same column of the periodic table as carbon (C) and silicon (Si). It's n=2 orbitals form similar bands to those in C and Si. The energy gap between the valence band and the conduction band in Ge is 0.67 eV. What kind of electrical properties would you expect Ge to have?

1. insulator
2. conductor
3. semiconductor
4. dielectric
5. ferromagnet

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Consider applying the Drude model to the motion of charge carriers in a neutral plasma. Imagine creating the plasma by applying a high voltage to a low pressure gas. Some of the electrons will separate from the neutral atoms creating positive and negative charges in the gas. The negative charges will move towards the positive terminal (anode) and the positive charges will move towards the negative terminal (cathode). Which charge carriers will make a bigger contribution to the conductivity of the plasma?

1. the negatively-charged electrons
2. the positively charged ions
3. They will both be the same.

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A thermistor is a device for measuring temperature based on the changing resistance of the device. A good thermistor is fairly linear in temperature. In other words, the resistance will be roughly proportional to the temperature. Which material would you expect would make a good thermistor?

1. a very pure metal
2. a metal with a few impurities
3. an alloy (mixture of metals)
4. a semiconductor
5. an insulator

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If an electric field is applied to a metal, the Fermi speed

1. increases.
2. decreases.
3. stays pretty much the same.

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Metals are hard to compress principly because of

1. the electrostatic repulsion of the ionic cores.
2. the electrostatic repulsion of the electrons.
3. the electrostatic attraction of electrons to the ionic cores.
4. degeneracy pressure.
5. resonant tunneling.

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What keeps an appropriately-sized neutron star from collapsing into a black hole?

1. The neutrons are packed as densely as possible without passing through each other.
2. The nuclear strong force is repulsive at short distances.
3. The neutrons decay into protons, electrons, and neutrinos if they get too close together.
4. The outward degeneracy pressure balances the inward gravitational pull.
5. The event horizon is too small to contain all of the neutrons.

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Why doesn't Bose-Einstein condensation happen in neutron stars?

1. They are too hot.
2. They are too cold.
3. They are too big.
4. Neutrons are fermions, not bosons.
5. Neutrons break up into protons, pions, and neutrinos too easily.
6. The gravitational force is too big.

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Which of the following are possible wave functions for a system of two identical bosons at position x₁ and x₂? (ignore normalization)

1. sin(x₁-x₂)
2. cos(x₁+x₂)
3. sin(kx₁)sin(kx₂)
4. x₁ - x₂
5. x₁x₂
6. x₁ + x₂

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Which of the following are possible wave functions for a system of two identical fermions at position x₁ and x₂? (ignore normalization)

1. sin(x₁-x₂)
2. cos(x₁+x₂)
3. sin(kx₁)sin(kx₂)
4. x₁ - x₂
5. x₁x₂
6. x₁ + x₂

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