Across
1
Center of an atom or cell
4
Unit of power
5
Amplified beam of light
6
Ball of burning gas in space
10
Smallest unit of an element
Down
2
Precious yellow metallic element
3
Positive particle in nucleus
5
Curved glass that refracts light
7
Chemical element in table salt
8
Push or pull on an object
9
Path of a planet around the sun