1. a) +1, b) +6, c) -4, d) +2, e) +4, f) +3, g) +1, h) +3, i) 0, j) +7
2. a. Valency is the combining capacity of an element, while oxidation number is the hypothetical charge on an atom if all bonds were ionic.
b. Activity series ranks metals by reactivity; electrochemical series ranks elements by standard electrode potential.
c. Oxidizing agent accepts electrons and gets reduced; reducing agent donates electrons and gets oxidized.
3. i) Oxidation number: The charge an atom would have if the compound was composed of ions.
ii) Redox couple: A pair of oxidized and reduced species involved in a redox reaction.
iii) Displacement redox reaction: A reaction where one element displaces another from its compound.
iv) Standard electrode potential: The voltage measured under standard conditions for a half-cell reaction relative to the standard hydrogen electrode.
v) Stock notation: A system using Roman numerals to indicate the oxidation state of an element in a compound.
vi) Disproportionation reactions: Reactions where a single species is both oxidized and reduced.
4. a) Redox (Cu reduced, H oxidized), b) Redox (Na oxidized, H reduced), c) Not redox (precipitation), d) Not redox (decomposition), e) Redox (C oxidized, C reduced)
5. a) i) +1, b) ii) -1, iii) +2, iv) -2, c) i) +1, ii) -1
6. a) 2MnO₄⁻ + 10Br⁻ + 16H⁺ → 2Mn²⁺ + 5Br₂ + 8H₂O
b) NO₃⁻ + 3Bi + 6H⁺ → Bi³⁺ + NO + 3H₂O
c) 2MnO₄⁻ + 5C₂H₂O₄ + 6H⁺ → 2Mn²⁺ + 10CO₂ + 8H₂O
Parent Tip: Review the logic above to help your child master the concept of oxidation reduction reactions worksheet.
