Periodic Table

1. Vertical column on the periodic table.
4. The average mass of all atoms of an element.
5. The smallest unit of an element that has all of the properties.
9. An atom that has lost or gained an electron.
11. Largest group on the periodic table.
14. The number of protons in the nucleus of an atom.
15. They have properties of metals and nonmetals.
16. An element that does not conduct electricity or heat and is usually a gas.
18. Second most reactive elements.
19. Group that contains 7 valence electrons.
20. Group with only one valence electron. Highly reactive.

2. Describes how likely an element is to form bonds with other elements.
3. An atom that has gained or lost neutrons.
6. An element that conducts heat and electricity.
7. a chart that organizes information about all of the known elements according to their atomic number.
8. A horizontal row in the periodic table.
10. The number of atoms in 1 mole of a substance.
12. Group 8A on the periodic table.
13. number The number of protons and neutrons in the nucleus of one atom.
17. A substance that cannot be broken down into a simpler substance by ordinary chemical means.