Question

How would you order the following elements with respect to electron affinity: `Cl^-, Ar, K^+, Ti, Ti^(+2)`?

Answer 1

`Ti^(+2) > K^+ > Ti > Cl^- "> Ar`

Explanation:

4 things affecting electron affinity

1. Shielding electrons
   

2. Effective nuclear charge

3. distance from the nucleus

4. Noble gases will have no electron affinity as they are non-reactive

Argon will have the lowest electron affinity as it is a noble gas

Compare Cl-, K+, Ti and `Ti^+2`

Cl- has already 1 extra electron and its negative so its electron affinity will be lower than K+, Ti, `Ti^+2`
Ti can take an electron and to become negative and can release an electron to become positive so its chances are neutral. So electron affinity of Cl < Ti < K+ and `Ti^+2`
Now compare Ti+2 and K+
K+ has lost one electron there are chances that it will grab another one but Ti+2 has more chances of grabbing an electron as it has already lost 2 electrons.
So the electron affinity of these ions and elements
`Ti^(+2) > K^+ > Ti > Cl^- "> Ar`