Across
1
Chemical element in table salt
3
Solid with repeating atomic pattern
4
Gas essential for breathing
5
Unit of electric potential
6
Substance with pH above 7
12
Unit of force
Down
2
Blocking of light by a celestial body
3
Icy body with a tail near the sun
7
Compound containing oxygen
8
Nerve cell in the brain
9
Measure of matter in an object
10
Precious yellow metallic element
11
Natural satellite of Earth
13
The Red Planet