What is the oxidation state of the K atom in KClO4?

1 Answer
Nov 3, 2015

+1

Explanation:

Rules to remember when trying to find out the oxidation state of an element:

(1) The total charge of a stable compound is always equal to zero (meaning no charge).

For example, the #H_2O# molecule exists as a neutrally charged substance.

(2) If the substance is an ion (either there is a positive or negative charge) the total oxidation state of the ion is the charge (i.e. oxidation state of #NO_3^"-1"# ion is -1).

(3) All elements from Group 1A has an oxidation state of +1 (e.g. #Na^"+1"#, #Li^"+1"#). All Group 2A and 3A elements have an oxidation state of +2 and +3, respectively. (e.g. #Ca^"2+"#, #Mg^"2+"#, #Al^"3+"#)

(4) Oxygen always have a charge -2 except for peroxide ion (#O_2^"2-"#) which has a charge of -1.

(5) Hydrogen always have a charge of +1 if it is bonded with a non-metal (as in the case of #HCl#) and always have a -1 charge if it is bonded with a metal (as in #AlH_3#).

For your question, #KClO_4#, based on rule 3, the answer is +1.