Across
1
Biological catalyst
3
Positive particle in nucleus
5
Path of a planet around the sun
8
Curved glass that refracts light
Down
2
Compound containing oxygen
4
Substance with pH above 7
6
Unit of electric potential
7
Solid with repeating atomic pattern
9
Precious yellow metallic element
10
Element found in all living things
11
The Red Planet
12
Gas form of a liquid