Solutions to Chapter 4 Exercises

4.1 Solutions

1. The protons in the nucleus do not change during normal chemical reactions. Only the outer electrons move. Positive charges form when electrons are lost.

3. P, I, Cl, and O would form anions because they are nonmetals. Mg, In, Cs, Pb, and Co would form cations because they are metals.

5. (a) P3^–; (b) Mg²⁺; (c) Al³⁺; (d) O^2–; (e) Cl^–; (f) C^s+

7. (a) [Ar]4s²3d¹⁰4p⁶; (b) [Kr]4d¹⁰5s²5p⁶ (c) 1s² (d) [Kr]4d¹⁰; (e) [He]2s²2p⁶; (f) [Ar]3d¹⁰; (g) 1s² (h) [He]2s²2p⁶ (i) [Kr]4d¹⁰5s² (j) [Ar]3d⁷ (k) [Ar]3d⁶, (l) [Ar]3d¹⁰4s²

9. (a) 1s²2s²2p⁶3s²3p¹; Al³⁺: 1s²2s²2p⁶;
(b) 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁵; 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶;
(c) 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s²; Sr²⁺: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶;
(d) 1s²2s¹; Li⁺: 1s²;
(e) 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p³; 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶;
(f) 1s²2s²2p⁶3s²3p⁴; 1s²2s²2p⁶3s²3p⁶

4.2 Solutions

1. NaCl consists of discrete ions arranged in a crystal lattice, not covalently bonded molecules.

3. ionic: (b), (d), (e), (g), and (i); covalent: (a), (c), (f), (h), (j), and (k)

5. (a) Cl; (b) O; (c) O; (d) S; (e) N; (f) P; (g) N

7. (a) H, C, N, O, F; (b) H, I, Br, Cl, F; (c) H, P, S, O, F; (d) Na, Al, H, P, O; (e) Ba, H, As, N, O

9. N, O, F, and Cl

11. (a) HF; (b) CO; (c) OH; (d) PCl; (e) NH; (f) PO; (g) CN

4.3 Solutions

1. Ionic: KCl, MgCl₂; Covalent: NCl₃, ICl, PCl₅, CCl4

3. (a) covalent; (b) ionic, Ba²⁺, O²⁻; (c) ionic, NH⁴⁺, CO₃²⁻; (d) ionic, Sr²⁺, H₂PO₄⁻; (e) covalent; (f) ionic, Na⁺, O²⁻

5. (a) CaS; (b) (NH₄)₂SO₄; (c) AlBr₃; (d) Na₂HPO₄; (e) Mg₃ (PO₄)₂

4.4 Solutions

1. (a) cesium chloride; (b) barium oxide; (c) potassium sulfide; (d) beryllium chloride; (e) hydrogen bromide; (f) aluminum fluoride

3. (a) RbBr; (b) MgSe; (c) Na2O; (d) CaCl₂; (e) HF; (f) GaP; (g) AlBr₃; (h) (NH₄)₂SO₄

5. (a) ClO2; (b) N2O4; (c) K3P; (d) Ag2S; (e) AlN; (f) SiO2

7. (a) chromium(III) oxide; (b) iron(II) chloride; (c) chromium(VI) oxide; (d) titanium(IV) chloride; (e) cobalt(II) oxide; (f) molybdenum(IV) sulfide

9. (a) K₃PO₄; (b) CuSO₄; (c) CaCl₂; (d) TiO₂; (e) NH₄NO₃; (f) NaHSO4

11. (a) manganese(IV) oxide; (b) mercury(I) chloride; (c) iron(III) nitrate; (d) titanium(IV) chloride; (e) copper(II) bromide