Answers to Chapter 12 Study Questions
1. A chemical bond is the force holding atoms together. Atoms form chemical bonds to acquire a stable number of electrons, which is often the same number of electrons as the nearest noble gas. Covalent bonds involve the sharing of electrons between atoms, so that both atoms act as if they've acquired the shared electrons. In ionic bonds, electrons are NOT shared; a metal atom gives up one or more electrons to form a positive ion, a nonmetal gains one or more electrons to form a negative ion, and then the two ions are attracted to each other due to their opposite charges. Both covalent bonding and ionic bonding are strategies by which an atom attains a stable number of electrons.
2. The number of bonds a nonmetal forms usually = 8 – valence.
3. Covalent bonds are found in molecules (covalent compounds and some nonmetal elements) and in polyatomic ions.
4. a) As < P < N b) Li < C < O c) K < Mg < B
5. a) H ¾ Cl b) F ¾ C
6. a) Li+ b) Na+ c) F
7. a) 1s22s22p6; N3-, F-, Na+, Mg2+, Al3+; Ne b) 1s22s22p63s23p6; S2-, Cl-, K+, Ca2+; Ar
8. Ca(s) + I2(s) ® CaI2(s)
9. a) Be b) C c) F
10. a) b) c) d)
e) f) g)
11. a) bent b) linear c) pyramidal d) tetrahedral
12. a) polar b) nonpolar c) polar d) polar