28. magnesium bromide is a binary ionic compound. from its formula, mgbr2, how do you know that mg is the metal? (pages 567-568)
29. element x has five valence electrons, element y has one valence electron, and element z has one valence electron. which two of these elements are most likely to have similar properties? explain your answer. (page 503)

See Below

Explanation:

28. In ionic compounds the metal is always at the left.

MgBr2

Cu(SO4)2

CaCO3

FeO

Li2O

etc

29.

Elements from same group are more likely to have similar properties.

Since Y and Z have one valence electron they are from the same group, therefore are more likely to have similar properties

the answer is to check all of them! they all apply well at least i think so!

mistakes are ok