Across
- 2. numbers are the number of protons in the nucleus of an atom.
- 4. are a substance that cannot be separated or broken down.
- 6. are a charged particle that forms when an atom or groups of atoms gain or lose one or more electrons.
- 7. property is a characteristic of a substance that does not involve a chemical change,such as density,color,or hardness.
Down
- 1. clouds are outside the nucleus where electrons can be found.
- 3. symbols are one,two or three letter abbreviations of the name of that element.
- 5. numbers are the sum of the numbers of protons and neutrons in the nucleus of an atom.