Across
1
Center of an atom or cell
2
Force that attracts objects together
4
Basic unit of life
8
Smallest unit of an element
10
Our home planet
Down
2
Precious yellow metallic element
3
Natural satellite of Earth
4
Reddish electrical conductor
5
Form of thermal energy
6
Curved glass that refracts light
7
Substance with pH above 7
9
Unit of electric potential