Across
1
Chemical element in table salt
4
Substance with pH above 7
6
Compound containing oxygen
9
Smallest unit of an element
10
Gas essential for breathing
Down
2
Naturally occurring inorganic solid
3
Unit of electric potential
5
Icy body with a tail near the sun
7
Tectonic landmass section
8
Biological catalyst
11
Force that attracts objects together
12
Precious yellow metallic element