Across
1
Unit of electric potential
4
Fourth state of matter
6
Gas essential for breathing
8
Naturally occurring inorganic solid
9
Icy body with a tail near the sun
11
Path of a planet around the sun
Down
2
Curved glass that refracts light
3
Form of thermal energy
4
Positive particle in nucleus
5
Measure of matter in an object
7
Substance with pH below 7
10
Smallest unit of an element