Across
1
Positive particle in nucleus
5
Precious yellow metallic element
6
Solid with repeating atomic pattern
7
Hottest planet in solar system
9
Mass per unit volume
11
Center of an atom or cell
Down
2
Curved glass that refracts light
3
Ball of burning gas in space
4
Group of similar cells
8
Substance with pH below 7
10
Push or pull on an object