Across
1
Center of an atom or cell
6
Substance with pH above 7
8
Unit of force
10
Gas form of a liquid
11
Mass per unit volume
Down
2
Natural satellite of Earth
3
Naturally occurring inorganic solid
4
Chemical element in table salt
5
Icy body with a tail near the sun
7
Amplified beam of light
9
Unit of power
12
Compound containing oxygen