Across
1
Blocking of light by a celestial body
5
Ball of burning gas in space
6
Particle of light
7
Basic unit of life
8
Substance with pH below 7
9
Element found in all living things
10
Smallest unit of an element
12
Glass that splits light into spectrum
Down
2
Positive particle in nucleus
3
Nerve cell in the brain
4
Solid with repeating atomic pattern
7
Reddish electrical conductor
11
Precious yellow metallic element
13
Measure of matter in an object