Structure of the Atom

2. the average mass of all the isotopes of an element
5. a class of elements characterized by physical properties
6. an element that lacks most of the properties of a metal
8. an atom with the same number of protons and a different number of neutrons from other atoms of the same element
10. an element in group 18 of the periodic table
11. the number of protons in the nucleus of an atom
12. the specific amount of energy an electron has
13. a positively charged particle that is part of an atom's nucleus
14. elements in the same vertical column of the periodic table
18. a chart of the elements showing the repeating pattern of their properties

1. a term used to describe materials that can be pulled out into a long wire
3. an element in group one of the period table
4. the sum of protons and neutrons in the nucleus of an atom
7. a one or two letter representation of an element
9. a negatively charged particle that is found outside the nucleus of an atom
13. a horizontal row of elements in the periodic table
15. the central core of the atom
16. a small particle in the nucleus of the atom
17. the ability of an object to transfer heat or electricity to another object
19. the basic particle from which all elements are made