Across
1
Substance with pH above 7
3
Precious yellow metallic element
5
Force that attracts objects together
6
Naturally occurring inorganic solid
9
Blocking of light by a celestial body
10
Chemical element in table salt
11
Biological catalyst
Down
2
Preserved remains of ancient life
4
Gas essential for breathing
7
Fourth state of matter
8
Center of an atom or cell