Across
1
Center of an atom or cell
6
Smallest unit of an element
7
Magnetic metallic element
9
Natural satellite of Earth
10
Force that attracts objects together
11
Absolute temperature scale unit
12
Measure of matter in an object
13
The Red Planet
Down
2
Icy body with a tail near the sun
3
Glass that splits light into spectrum
4
Hottest planet in solar system
5
Substance with pH above 7
8
Path of a planet around the sun