1. 1. The central core of the atom, containing protons and usually neutrons
NUCLEUS

2. PROTON
Small positively charged particles that are found in the nucleus of an atom

3. NEUTRON
Small uncharged particles that are found in the nucleus of an atom

4. ELECTRON
Tiny, negatively charged, high-energy particles that move around outside the nucleus of an atom

5. VALENCE ELECTRONS
The electrons that are farthest away from the nucleus of an atom and are involved in chemical interactions.

6. ELECTRON DOT DIAGRAM
A representation of the number of valence electrons in an atom, using dots placed around the symbol of an element

7. ATOMIC NUMBER
The number of protons in the nucleus of an atom

8. GROUP
Elements in the same vertical column of the periodic table. Also called family.

9. PERIOD
Elements in the same horizontal row of the periodic table.

10. HALOGEN REACTIVE NON METAL
An element belonging to Group 17 of the periodic table.

11. ION
An atom or group of atoms that has become electrically charged.

12. IONIC BOND
The attraction between oppositely charged ions.

13. POLYATOMIC ION
An ion that is made of more than one atom.

14. CRYSTAL
An orderly, three-dimensional pattern of ions or atoms in a solid.

15. MINERAL
A naturally occurring solid that has a crystal structure and a definite chemical composition.