44. (a) N2O3 (b) SF4 (c) AlCl3 (d) Li2CO3 46. H Br δ+ δ− 48. The metallic potassium atoms lose one electron and form +1 cations, and the nonmetallic fluorine atoms gain one electron and form –1 anions. K → K+ + e– 19p/19e– 19p/18e– F + e– → F– 9p/9e– 9p/10e– The ionic bonds are the attractions between K+ cations and F– anions. 50. See Figure 3.6. 52. (a) covalent…nonmetal-nonmetal (b) ionic…metal-nonmetal 54. (a) all nonmetallic atoms - molecular (b) metal-nonmetal - ionic 56. (a) 7 (b) 4 58. Each of the following answers is based on the assumption that nonmetallic atoms tend to form covalent bonds in order to get an octet (8) of electrons around each atom, like the very stable noble gases (other than helium). Covalent bonds (represented by lines in Lewis structures) and lone pairs each contribute two electrons to the octet. (a) oxygen, O If oxygen atoms form two covalent bonds, they will have an octet of electrons around them. Water is an example: H O H (b) fluorine, F If fluorine atoms form one covalent bond, they will have an octet of electrons around them. Hydrogen fluoride, HF, is an example: H F (c) carbon, C If carbon atoms form four covalent bonds, they will have an octet of electrons around them. Methane, CH4, is an example: H H H H C (d) phosphorus, P If phosphorus atoms form three covalent bonds, they will have an octet

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