Across
1
Fourth state of matter
3
Solid with repeating atomic pattern
4
Blocking of light by a celestial body
5
Nerve cell in the brain
12
Magnetic metallic element
Down
2
Center of an atom or cell
3
Icy body with a tail near the sun
6
Mass per unit volume
7
Unit of energy
8
Compound containing oxygen
9
Disturbance that transfers energy
10
Gas form of a liquid
11
Biological catalyst