Across
1
Precious yellow metallic element
3
Glass that splits light into spectrum
5
Positive particle in nucleus
7
Particle of light
8
Naturally occurring inorganic solid
10
Form of thermal energy
Down
2
Center of an atom or cell
4
Force that attracts objects together
5
Fourth state of matter
6
The Red Planet
9
Nerve cell in the brain
11
Hottest planet in solar system