Across
1
Center of an atom or cell
4
Precious yellow metallic element
5
Path of a planet around the sun
6
Naturally occurring inorganic solid
8
Unit of electric potential
Down
1
Unit of force
2
Compound containing oxygen
3
Curved glass that refracts light
6
Measure of matter in an object
7
Preserved remains of ancient life
9
Substance with pH below 7