Describe in your own words why lithium, magnesium, and boron (groups 1,2,13) elements tend to form positive ions and fluorine, oxygen, and nitrogen (groups 15,16,17) tend to form positive ions.

Group 1,2,13 has valence electron less than 5 so it will donate electron to form pasitive ion while element group15,16,17 has valence electron more than 5 so it will receive electron to form negative ion actually, not positive ion dude!