Question

Explain why:

(1) Fluorine has a lower electron affinity than chlorine.
(2) Red phosphorus is less reactive than white phosphorus.
(3) Ozone acts as a powerful oxidising agent.

Answer 1

(1) 

F₉ – 1s²2s²2p⁵
Cl₁₇ – 1s²2s²2p⁶3s²3p⁵

This is because in fluorine there is strong electron-electron repulsion for the incoming electron due to the relatively compact size of 2p-orbitals in fluorine as compared to 3p-orbitals in chlorine.

(2)

This is because, in red phosphorus, there are strong covalent bonds in P₄ molecules but in white phosphorus, there are Van der Waals forces of attraction in P₄ molecules.

(3)

This is because O3 molecules readily dissociate to give nascent oxygen which oxidises other substances.
O₃ → O₂ + [O] Nascent oxygen