Across
- 2. A group of highly reactive nonmetals in the second-to-last column (Group 17) of the periodic table.
- 4. The number of protons in the nucleus of an atom. It defines which element an atom is.
- 8. Imaginary regions around the nucleus of an atom where electrons are likely to be found. Each shell can hold a maximum number of electrons.
- 9. The total number of protons and neutrons in the nucleus of an atom.
- 10. A chart that organizes all known elements based on their atomic number and chemical properties.
Down
- 1. A group of very unreactive gases in the last column (Group 18) of the periodic table.
- 3. A group of highly reactive metals in the first column (Group 1) of the periodic table (excluding hydrogen).
- 5. The arrangement of electrons within the different shells and subshells of an atom.
- 6. Specific, discrete amounts of energy that electrons in an atom can have. Electrons can only exist at these allowed energy levels.
- 7. The forces of attraction or repulsion between charged particles. Opposite charges attract, and like charges repel.