Across
1
Smallest unit of an element
4
Compound containing oxygen
6
Solid with repeating atomic pattern
7
Curved glass that refracts light
10
Path of a planet around the sun
11
Center of an atom or cell
Down
2
Ball of burning gas in space
3
Unit of energy
5
Preserved remains of ancient life
8
Nerve cell in the brain
9
Group of similar cells