1						2
			3
														4
				5
		6
							7
8											9
10																11
			12
										13
14
							15

Across 2. Transform from one form to another 3. A substance that mixes with another substance evenly and dissolves 5. The number of protons in the nucleus of an atom. This number identifies the atom 8. Subatomic particle with a positive charge and located in the nucleus of the atom. 12. The average mass number of all isotopes of an atom. Round this number to find the mass number of the atom. 13. The central part of the atom, containing protons and neutrons. 14. A characteristic of a substance that can be observed. 15. Subatomic particle with no charge, the same mass as a proton, and located in the nucleus of the atom.

Down 1. Region surrounding the nucleus of an atom, where electrons are most likely to be found 4. Subatomic particle with a negative charge and located outside the nucleus 6. The smallest unit of matter that retains the identity of the substance. 7. Ability to be stretched into a thin wire 9. The number of protons and neutrons in the nucleus of an atom. Protons + Neutrons = ? 10. Atom with the same number of protons but a different number of neutrons of the same element. 11. Amount of matter contained in a substance