Unit 2 words

2. small, dense region consisting of protons and neutrons.
3. earth metals They are reactive, electropositive, divalent metals, and form basic oxides which react with water to form comparatively insoluble hydroxides.
7. electrons an electron in the outer shell associated with an atom.
8. metals a group of metals in the middle of the periodic table that have some similar properties with one another.
10. basic unit of a chemical element.
13. exist outside of and surrounding the atom nucleus.
16. subatomic particle with a positive charge.
18. in contact with air, water or other common substances, vigorously or violently give off heat, energy or toxic gases or vapors.
20. is a column of elements in the periodic table of the chemical elements.
22. a chemical element that forms a salt when it reacts with metal.
23. a molecule with a positive or negative charge.

1. metal are very reactive, electropositive, monovalent metals forming strongly alkaline hydroxides.
4. a type of subatomic particle with no charge.
5. chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals.
6. a row of chemical elements.
9. atoms that have the same atomic number and position in the periodic table.
11. shows a lustrous appearance, and conducts electricity and heat relatively well.
12. charge cations
14. radius the total distance from an atom's nucleus to the outermost orbital of electron.
15. gasses a class of chemical elements with similar properties; under standard conditions, they are all odorless.
17. group of atoms that bears one or more positive or negative electrical charges.
19. negatively charged ion
21. model a system consisting of a small, dense nucleus surrounded by orbiting electrons
24. metals substance that is not a metal.