Across
1
Solid with repeating atomic pattern
5
The Red Planet
7
Gas essential for breathing
8
Center of an atom or cell
10
Disturbance that transfers energy
11
Second lightest element
Down
2
Tissue that contracts for movement
3
Particle of light
4
Mass per unit volume
6
Unit of electric potential
9
Reddish electrical conductor
12
Element found in all living things