Question

1. what types of noncovalent interactions hold together the following solids?

(a) table salt (nacl), which contains $ce{na+}$ and $ce{cl-}$ ions.
(b) graphite (c), which consists of sheets of covalently bonded carbon atoms.

Explanation:

(a) Table salt (NaCl) is an ionic solid, held together by electrostatic attractions between positively charged $\text{Na}^+$ ions and negatively charged $\text{Cl}^-$ ions; these are ionic interactions, a type of noncovalent force.
(b) Graphite has covalently bonded carbon sheets, and the sheets are held together by weak London dispersion forces (a type of van der Waals force), which are noncovalent interactions.

Answer:

(a) Ionic interactions (electrostatic attractions between $\text{Na}^+$ and $\text{Cl}^-$ ions)
(b) London dispersion forces (van der Waals forces between carbon sheets)