Across
1
Icy body with a tail near the sun
3
Positive particle in nucleus
4
Absolute temperature scale unit
5
Ball of burning gas in space
6
Precious yellow metallic element
7
Substance with pH above 7
10
Magnetic metallic element
12
Amplified beam of light
Down
2
Compound containing oxygen
3
Particle of light
5
Chemical element in table salt
8
Substance with pH below 7
9
Molten rock beneath Earth surface
11
Preserved remains of ancient life
13
Element found in all living things