Question

Match the element or group to the rule assigning its oxidation state.

Answer 1

It would go B. A. E. D. C.
Hope I helped!

Answer 2

C. Lone elements and atoms in gases : 0

Elements in the free elemental have an oxidation number of zero

E. Elements in groups 1, 2, and 17 and polyatomic ions : Ionic charge

Group 1, 2, and 17 ions are formed by the alkali metals, alkaline metals and halogens respectively. Alkali metals, alkaline metals and halogens form +1, +2 and -1  ions respectively. Polyatiomic ions have -1, -2, -3 charges such as OH-, CO32-, PO43- respectively.

B. Hydrogen : +1, – 1 if bonded to a diatomic metal

H has an oxidation number of +1. H in metal hydrides such as NaH (sodium hydride) has an oxidation number of -1

A. Oxygen : Almost always –2  

O has an oxidation number of -2.

D. Elements with multiple oxidation states : Determined by other elements in the compound

V (vanadium) has different oxidation which depends on the compound in which V is found.