The crystal structure of an ionic compound depends on the . a) sizes of cations and anions. b) ratio of cations to anions. c) masses of cations and anion. d) both a and b

The crystal structure of an ionic compound depends on the sizes of cations and anions, as well as the ratio of cations to anions. The ratio of the cations and anions need to be even, otherwise, the crystal won't form.
 
So the answer would be D, both A and B. 

A. volume stays constant. just took took the quiz

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom