Question

Of the groups below, which are the least chemically reactive?
a) Group 3A elements
b) Group 1A elements
c) Group 2A elements
d) Group 7A elements

Explain why please! I think it has something to do with the valence electrons and the electronegativity, but I can't figure it out.

Answer 1

you are correct, but you have not chosen the least reactive group yet.

as a simple model, atoms want to have a full set of valence electrons. the elements with a full set are the noble gases in group viii, He, Ne, Kr, etc. Group vii elements such as F, Cl only need one more electron to get to that state, and have a strong ability to rip them away from other atoms, hence their high electronegativity. Group I elements just need to get rid of an electron to get to the desired noble gas configuration, so they also react easily. As you proceed toward the middle of the periodic table, more and more electrons need to be removed to get to that full outer shell state, until at some point the easier route will be adding electrons.

Answer 2

@whpalmer4 Okay, that is EXACTLY what I was thinking, thank you. I chose group 3A. I just needed someone to reassure me because it never talked about the middle of the periodic table and how reactive they are in the textbook. Sometimes they don't explain things because the topic too complicated to explain, but turns out I was right. Anyways, thank you so much!!!!!