The electronegativity of germanium is 1.8; that of bromine is 2.8 on the Pauling scale. Will they form an ionic bond?

The answer to your question is No.

Explanation:

Data

Electronegativity of Ge = 1.8

Electronegativity of Br = 2.8

The Ionic bond definition is the union of a metal and a nonmetal which difference of electronegativity is 1.7 or higher.

The Covalent bond definition is the union of two nonmetals which difference of electronegativity is lower than 1.7.

Calculate the difference of electronegativity between the Ge and Br.

ΔE = 2.8 - 1.8

ΔE = 1

This elements do not form an ionic bonding, they form a covalent bond.