Question

The halogens (group 17 elements) :

• A. have an electronic configuration of a noble gas
• B. are highly electropositive character
• C. show variable oxidation state of -1, +1, +3, +5 and +7 in their various compounds
• D. forms a volatile, covalent hydrides HX in which the halogen (X) shows an oxidation state of +1

Answer 1

The correct option is C show variable oxidation state of -1, +1, +3, +5 and +7 in their various compounds

Chlorine, bromine, and iodine have available d-orbitals, therefore paired electrons in the s and p orbitals can be unpaired by promoting them to the vacant d-orbitals thus opening the possibility of variable oxidation states of $-1$, $+1$, $+3$, $+5$ and $+7$.