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