Across
1
Infectious microscopic agent
3
Center of an atom or cell
5
Smallest unit of an element
6
Naturally occurring inorganic solid
7
Substance with pH above 7
11
Positive particle in nucleus
Down
1
Hottest planet in solar system
2
Preserved remains of ancient life
4
The Red Planet
8
Second lightest element
9
Force that attracts objects together
10
Mass per unit volume