What is the bond preference for bromine?

Answer 1

Bromine has 7 electrons in its outer shell and can achieve the octet either by sharing an electron in a covalent bond or by taking an electron to to form the bromide anion. In each case it is "monovalent".

Answer 2

Bromine prefers to form covalent bonds because it is a halogen and tends to share electrons with other atoms to achieve a full outer electron shell. It can form both polar and nonpolar covalent bonds depending on the electronegativity of the atoms it is bonding with.