Photons and Electrons

Question 1

True or false: frequency and wavelength are directly related.

Answer 1

False. They are inversely related.

Question 2

How is the binding energy of an electron calculated?

Answer 2

By multiplying Planck’s constant by the threshold frequency of the metal. (hxv)

Question 3

What is the effect of a higher frequency (much higher than threshold) of light on a metal?

Answer 3

The electrons emitted have greater kinetic energy, since the light wave itself has more energy.

Question 4

What is the effect of a brighter light (having a frequency above threshold) on a metal?

Answer 4

More electrons will be emitted from the metal, since more photons have been hitting it.

Question 5

What is photoionization?

Answer 5

The absorption of a photon by an atom which causes an electron to be emitted.

Question 6

When is an electron most stable?

Answer 6

When it is bound to a nucleus at the most negative energy level possible.

Question 7

What happens when light is absorbed by an atom at a frequency lower than threshold?

Answer 7

The electrons are excited and emit visible light in order to return to ground state.

Question 8

True or false: particles diffract when they experience interference.

Answer 8

False.

Question 9

What is the Uncertainty Principle?

Answer 9

It states that the more accurately we know the position of an electron, the more uncertain we are of its motion, and vice versa.

Question 10

What is the difference between an orbit and an orbital?

Answer 10

An orbit is a path supposedly followed by an electron.

An orbital is the area where a particular electron could be at any given time (calculated mathematically).

Question 11

What does the quantum number n signify?

Answer 11

A particular energy level or shell of an atom.

Question 12

What does the quantum number l signify?

Answer 12

The shape of an atomic orbital (s, p, d, or f).

Question 13

What does the quantum number m(l) signify?

Answer 13

The spatial orientation of an atomic orbital.

m(l)=2l+1

Question 14

What does the quantum number m(s) signify?

Answer 14

The spin of a particular electron. This value is either +1/2 or -1/2.

Question 15

Does the amplitude of a wave of light cause more electrons to be emitted from a metal?

Answer 15

Only when the frequency of the wave is greater than the threshold frequency for the metal.

Question 16

The electrons in a 3p orbital are screened by which electrons?

Answer 16

The electrons in the 1s and 2s orbitals.

Question 17

Can two or more electrons have the same values for all the quantum numbers, n, l, m(l), and m(s)?

Answer 17

NEVER. That would break physics.

Meaning that it is impossible.

Question 18

How many electrons are found at n=2, l=1, m(l)=0?

Answer 18

2

Question 19

Define the term ‘isoelectronic’.

Answer 19

It describes different atoms or molecules which have the same total electron count.

Question 20

When a transition metal is ionized, does it lose electrons in d orbitals first, or s orbitals?

Answer 20

It loses the electrons in the valence s orbital first.

Question 21

What is the difference between paramagnetism and diamagnetism?

Answer 21

Diamagnetism is stronger, and is a property of atoms in which every electron is paired up. Paramagnetism is weaker, and is a property of atoms which have unpaired electrons.

Question 22

Which two transition metals have a half-filled 4s orbital beneath their partially-filled 3d orbitals?

Answer 22

Copper and chromium.