CO2 and HBr have covalent bonds/ are covalent compounds.
Explanation:
Covalent bond are formed by mutual sharing of electrons like CO2 is covalent compounds, in which carbon has four valence shell electrons which form two double covalent bonds with two oxygen atoms to complete their valence shell. Similarly HBr is also covalent compound, in which Br has 7 valence shell electrons which complete their valence shell by making covalent bond with H by sharing of one electron..
Ionic bond are formed when one atom looses electron while other one accept. As MgO case, Mg looses two electrons while O accept two electrons and from ionic bond. NaCl is also ionic bond , Na looses electrons while chlorine accept electron.
