Question

how are ionization energy and electron affinity related? (choose all that apply.)
ionization energy refers to removing an electron while electron affinity refers to adding an electron.
electron affinity is essentially the opposite of ionization energy.
both ionization energy and electron affinity are measured in the gas phase of atoms.
both ionization energy and electron affinity are endothermic processes.
32 multiple choice 1 point
which element has the electron configuration $1s^2 2s^2 2p^5$?
br
i
f
cl
33 multiple choice 1 point
when an electron in hydrogen falls from the fifth energy level to the second energy level, it gives off blue light. why?
photons and electrons are the same thing according to the photoelectric effect.
energy is only given off when electrons move up in energy, not down.
the color given off is random and not predictable.
the energy difference between the fifth and the second energy level corresponds to the energy of blue light.

Explanation:

First Question (Ionization Energy and Electron Affinity)

1. First Option: Ionization energy is the energy to remove an electron ($X

ightarrow X^+ + e^-$), electron affinity is the energy change when an electron is added ($X + e^-
ightarrow X^-$), so this is correct.

1. Second Option: Ionization energy (removing e⁻) and electron affinity (adding e⁻) are opposite processes, so this is correct.
2. Third Option: Both are typically measured for gaseous atoms to avoid intermolecular interactions, so this is correct.
3. Fourth Option: Electron affinity is often exothermic (energy released when adding e⁻ to many atoms), while ionization energy is endothermic. So this is incorrect.

Step 1: Calculate Total Electrons

The electron configuration \(1s^2 2s^2 2p^5\) has \(2 + 2 + 5 = 9\) electrons. In a neutral atom, electrons = protons = atomic number.

Step 2: Identify Element by Atomic Number

• Br (Bromine): Atomic number 35
• I (Iodine): Atomic number 53
• F (Fluorine): Atomic number 9
• Cl (Chlorine): Atomic number 17

Fluorine has atomic number 9, matching the electron count.

• Option 1: Photons (light) and electrons are distinct; the photoelectric effect shows photons eject electrons, not that they are the same. Incorrect.
• Option 2: Electrons release energy (photons) when moving from higher to lower energy levels (down), absorb energy when moving up. Incorrect.
• Option 3: The color (photon energy) is determined by the energy difference between levels, so it is predictable. Incorrect.
• Option 4: When an electron falls from \(n=5\) to \(n=2\) in H, the energy difference (\(\Delta E\)) corresponds to the energy of a blue - light photon (\(E = h

u\), where \(
u\) is frequency, and color depends on frequency/energy). Correct.

Answer:

• Ionization energy refers to removing an electron while electron affinity refers to adding an electron.
• Electron affinity is essentially the opposite of ionization energy.
• Both ionization energy and electron affinity are measured in the gas phase of atoms.

Question 32 (Element with Electron Configuration \(1s^2 2s^2 2p^5\))