(i) 1s 2 2s 2 2p 6 3s 1 (ii) 1s 2 2s 2 2p 6 3s 2 (iii) 1s 2 2s 2 2p 6 3s 2 3p 1 (iv) 1s 2 2s 2 2p 6 3s 2 3p 4 (v) 1s 2 2s 2 2p 6 3s 2 3p 5 The electron configuration of the atom that is expected to have a positive electron affinity is .

 (V) 1s 2 2s 2 2p 6 3s 2 3p 5

Explanation:

Electron Affinity can be defined as the energy associated with a neutral atom, when an electron is added to form a negative ion.

1s 2 2s 2 2p 6 3s 2 3p 5 , is the electronic configuration of Chlorine.

The electron affinity is positive because it is an exorthermic reaction, meaning that, energy was released during the addition of an electron to the atom.

Cl (g)  +  e-   >  Cl- (g)    = -349KJ/mol