Across
1
Gas essential for breathing
3
Ball of burning gas in space
5
Substance with pH above 7
6
Hottest planet in solar system
7
Unit of energy
8
Positive particle in nucleus
11
Unit of power
Down
2
Preserved remains of ancient life
4
Disturbance that transfers energy
8
Particle of light
9
Push or pull on an object
10
Center of an atom or cell
12
Precious yellow metallic element