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!

29.1-12=17.1the answer is this one

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later