Across
1
Amplified beam of light
4
Particle of light
8
Magnetic metallic element
10
Unit of electric potential
11
Second lightest element
Down
2
Center of an atom or cell
3
Path of a planet around the sun
5
Icy body with a tail near the sun
6
Measure of matter in an object
7
Reddish electrical conductor
9
Positive particle in nucleus