Question

The properties of two elements are listed below.

Element
Atomic radius
(pm)
Ionic radius
(pm)
First ionization energy
(kJ/mol)
Electron affinity
(kJ/mol)
Electronegativity
Br
114
195
1140
–325
3.0
K
243
152.2
418.8
–48.4
0.82

Which prediction is supported by the information in the table?
K will give up an electron more easily than Br.
Both K and Br will have the same pull on electrons.
K will have a smaller size in comparison to Br.
Both K and Br will produce ions of the same size.

Answer 1

K will give up an electron more easily than Br.

Justification: K has a much lower first ionization energy (418.8 kJ/mol) than Br (1140 kJ/mol), so it requires far less energy to remove an electron. The low electronegativity and small (less negative) electron affinity of K also support that it more readily loses than gains an electron.