Across
1
Positive particle in nucleus
4
Blocking of light by a celestial body
9
Smallest unit of an element
11
Element found in all living things
12
Precious yellow metallic element
Down
2
Infectious microscopic agent
3
Icy body with a tail near the sun
5
Absolute temperature scale unit
6
Tectonic landmass section
7
Curved glass that refracts light
8
Fourth state of matter
10
Compound containing oxygen