Which pair of ions is most likely to form an ionic bond? A.
N3- and O2-
B.
H- and H-
C.
Na+ and Al3+
D.
Mg2+ and Br-

the atomic mass is the bottom number on the element.

-steel jelly

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).