Across
- 2. an atom that has more electrons than protons
- 3. the mass of an atom; equals the number of protons plus the number of neutrons
- 4. the centre of an atom-contains protons and neutrons
- 6. the area around the nucleus where the electrons travel
- 11. describes the electrons moving around in each shell
- 13. total number of protons in an atom;defines what atom it is
- 15. a substance that contains only two or more type of atom
- 16. positively charged particles in the nucleus of an atom
- 17. an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
- 18. theory that all matter is is made up of atoms
- 20. vertical column on the periodic table
- 21. a substance that only contains one type of atom
Down
- 1. parts that make up an atom
- 4. neutral particles found in the nucleus of an atom
- 5. negatively charged particles found orbiting the nucleus of an atom
- 7. an ion, or charged particle that has more protons than electrons.
- 8. a table that lists all the elements in order of their atomic number
- 9. smallest part of matter. contains protons, neutrons and electrons
- 10. horizontal row on the periodic table
- 12. A form of a chemical element in which the atoms have the same number of protons but with a different number of neutrons
- 14. an obsolete model of the atom, presented by Niels Bohr in 1913.
- 19. different energy levels where electrons orbit the nucleus