Types of chemical bonds
Answers are for parents and teachers.
1
Find the oxidation state of N in HNO₃ and of C in CaCO₃.
N: +5; C: +4.
2
Group NaCl, CO₂, Cu, H₂ by bond type.
NaCl — ionic; CO₂ — polar covalent; Cu — metallic; H₂ — nonpolar covalent.
3
In the reaction of Na with Cl₂, which atom is oxidised and which is reduced?
Na – e⁻ → Na⁺ is oxidised; Cl + e⁻ → Cl⁻ is reduced.
4
Why is hydrogen –1 in CaH₂?
Ca is a metal (+2) and in a metal hydride H is –1: +2 + 2·(–1) = 0.
5
Explain the difference between an ionic and a polar covalent bond.
In an ionic bond the pair transfers fully and ions form; in a polar covalent bond the pair is only partly shifted.