In a similar fashion to alcohols, alkyl halides are usually described by their substitution as primary (1o), secondary (2o) or tertiary (3o) depending on how many alkyl substituents are attached to the C-X unit. Alkyl halide reactivity is very dependent upon this substitution pattern.
Due to the polarity of the covalent bond between the halogen and the alkyl group, melting points and boiling points are higher than those of alkanes with similar carbon lengths and branching patterns. However, these dipole-dipole interactions are not as strong as the hydrogen-bonding in alcohols.
Since all halogens are electronegative, the adjacent electron-poor carbon typically acts as an electrophile. Most all reactions of alkyl halides (like substitution reactions, SN1 and SN2) will show them in this electrophilic role. Also due to the electronegativity of halogens, they make decent leaving groups, which you again will observe in substitution and elimination reactions.