Across
1
Chemical element in table salt
3
Curved glass that refracts light
6
Reddish electrical conductor
9
Fourth state of matter
10
Hottest planet in solar system
11
Preserved remains of ancient life
12
Nerve cell in the brain
Down
2
Positive particle in nucleus
4
Center of an atom or cell
5
Unit of electric potential
7
Compound containing oxygen
8
Push or pull on an object