Across
1
Molten rock beneath Earth surface
4
Nerve cell in the brain
6
The Red Planet
7
Solid with repeating atomic pattern
12
Mass per unit volume
13
Tectonic landmass section
Down
2
Icy body with a tail near the sun
3
Chemical element in table salt
5
Smallest unit of an element
8
Second lightest element
9
Hottest planet in solar system
10
Unit of force
11
Amplified beam of light