Across
- 2. It is a column of elements in the periodic table.
- 6. Its the mass of an atom.
- 7. A table of chemical elements.
- 9. Substance that can not be broken down into simpler substances by chemical means.
- 11. A particle smaller then an atom.
- 13. A subatomic particle of about the same mass as a proton but without an electric charge.
Down
- 1. The central part atom it contains the protons and neutrons.
- 3. It a horizontal roe of the periodic table.
- 4. Is the basic unit of a chemical element.
- 5. An outer shell of electrons.
- 8. A stable subatomic particle with a charge of negative electricity.
- 10. Were the electrons are located around the nucleus.
- 12. Is a positive charge and its located in the nucleus.