Chemistry C2 - Ions and Formulas

Groups 1&2 and 6&7 are the most likely to form ions 

1) remember; atoms that have lost or gained electron(s) are ions 

2) Ions have the electronic structure of a noble gas 

3) groups 1,2,6,7 are the the elements most likely to form ions 

4) Group 1&2 (metals) - lose electrons to form positive ions 

5) group 1 elements (alkali metals) form ionic compounds with non metals eg: K+Cl- 

6) group 6&7 (non metals) gain electrons to form negative ions 

7) group 7 (the halogens) form ionic compounds…