Across
- 1. particle of an atom with a mass of +1
- 4. the first noble gas in the periodic table
- 5. Fluorine and chlorine are part of this group of elements
- 8. the number of element in the outer shell of a noble gas
Down
- 1. the resulting charge of an atom after oxidation
- 2. the atomic ------ is equal to the number of protons in an atom
- 3. a negatively charge particle of an atom
- 6. the centre area of an atom
- 7. all elements are made of these
- 9. the vertical columns of a periodic table