These are four questons and four answers:
Answers:
Explanation:
Question 1) Cl₂O₇:
a) Net charge of the compound: 0
b) Rule: oxygen works with oxidation state +2, except with peroxides.
d) Rule: balance of charges: ∑ of the charges = net charge
Call X the oxidation number of Cl:
Conclusion: the oxidation number of Cl in Cl₂O₇ is 7⁺.
Question 2) AlCl₄⁻
a) Net charge of the ion: - 1
b) Rule: common oxidation number of Al in compounds: +3
c) Rule: balance of charges: ∑ charges = net charge = - 1
Conclusion: the oxidation number of Cl in AlCl₄⁻ is 1 ⁻.
Question 3) Ba(ClO₂)₂
a) Net charge of the compound: 0
b) Rule: common oxidation number of BA in compounds: +2
c) Rule: common oxidation number of O in compounds (except in peroxides): -2
d) Rule: balance of charges: ∑ charges = net charge = 0
Conclusion: the oxidation number of Cl in Ba(ClO₂)₂ is 3⁺.
Question 4) CIF₄⁺
a) Net charge of the ion: + 1
b) Rule: common oxidation number of F : - 1 (it is the most electronegative)
c) Rule: balance of charges: ∑ charges = net charge = + 1
Conclusion: the oxidation number of Cl in ClF₄⁺ is 5⁺.