Chapter 7 - Ionization energy and electron affinity

What is ionization energy?

the energy required to remove an electron from an atom

How does ionization energy change after removing the first

It requires more and more energy to remove electrons after the first. When all valence electrons have been removed, it takes a substantial amount more energy to remove core electrons

How does ionization energy (I) change across the periodic table

generally - increases across a period, decreases down a group

Lowest ionization energy bottom left

Highest top right

What are factors that impact ionization energy

Smaller atoms have higher I values

I values depend on the effective nuclear charge

What is the group 2A-3A disconinuity in ionization energy

The electron is removed from the p orbital rather than the s orbital. Ionization energy in group 3A is less than 2A. It is easier to remove electrons from orbitals that are not full

What is the group 5A-6A discontinuity

It is easier to lose electrons in group 6A (oxygen group) than group 5A.

What is the electron configuration of ions

Cations - The electrons are lost from the highest energy level. Li+ is 1s^2, as it lost the 2s electron

Anions - The electron configurations are filles to ns^2 np^6. F- is 1s^2 2s^2 2p^6

What is electron affinity

the energy change that occurs when an electron is acquired by a neutral atom

Is electron affinity exothermic or endothermic

exothermic

What are the general trends for electron affinity across the periodic table

Generally, across a period negativity increases.

What are three exceptions for the trends of electron affinity

Group 2A - S sublevel is full

Group 5A - P sublevel is half-full

Group 8A - P sublevel is full

The electron affinity for these periods is lower than expected