Question

research worksheet: ionization energy and electron affinity
in this research activity, you will investigate two important periodic - electron affinity. these properties explain how atoms gain or lose a - and reactivity. use your textbook, class notes, and reliable online resources to complete
part a: ionization energy

1. define ionization energy in your own words.
2. what happens to an atom when it loses an electron?
3. which element has the highest ionization energy, and why?
4. describe the trend in ionization energy across a period (left to right).
5. describe the trend in ionization energy down a group (top to bottom).
6. why does ionization energy generally increase across a period?

part b: electron affinity

1. define electron affinity in your own words.
2. which element has the highest electron affinity, and why?
3. describe the trend in electron affinity across a period.
4. describe the trend in electron affinity down a group.
5. why do noble gases have very low or no electron affinity values?
6. compare and contrast ionization energy and electron affinity.

Explanation:

1. Ionization energy is the energy required to remove an electron from a gaseous atom or ion. When an atom loses an electron, it becomes a positively - charged ion (cation). Helium has a very high ionization energy due to its small size and stable electron configuration. Across a period (left to right), ionization energy generally increases because the nuclear charge increases and the atomic radius decreases, making it harder to remove an electron. Down a group, ionization energy decreases as the outermost electrons are farther from the nucleus and less tightly held. Ionization energy increases across a period because of the increasing nuclear charge and decreasing atomic size.
2. Electron affinity is the energy change that occurs when an electron is added to a gaseous atom. Chlorine has a high electron affinity because it can achieve a stable noble - gas electron configuration by adding an electron. Across a period, electron affinity generally increases (with some exceptions). Down a group, electron affinity generally decreases. Noble gases have very low or no electron affinity because they have a stable electron configuration and adding an electron would disrupt this stability. Ionization energy is about removing an electron, while electron affinity is about adding an electron.

Answer:

1. Ionization energy: The energy needed to remove an electron from a gaseous atom/ion.
2. Becomes a positively - charged ion (cation).
3. Helium; due to small size and stable configuration.
4. Generally increases.
5. Generally decreases.
6. Increasing nuclear charge and decreasing atomic size.
7. Electron affinity: The energy change when an electron is added to a gaseous atom.
8. Chlorine; to achieve stable configuration.
9. Generally increases (with exceptions).
10. Generally decreases.
11. Stable electron configuration; adding an electron disrupts it.
12. Ionization energy: Removing an electron. Electron affinity: Adding an electron.