Question

These models show the electron structures of two different nonmetal elements.

Element 1 at left has a purple circle at center with 2 concentric black lines around it. The first line has 2 small green balls on it. The second line has 8 small green balls on it. Element 2 at right has a purple center with 5 concentric circles around it, with the first circle innermost. The first circle has 2 small green balls on it, and the second circle has 8 small green balls on it. The third circle has 18 small green balls on it, and the fourth circle has 18 small green balls on it. The fifth circle has 6 small green balls on it.

Which element is likely more reactive, and why?

Element 1 is more reactive because it has fewer electron shells and is toward the top of its group on the periodic table.
Element 1 is more reactive because it has more electrons in its valence shell and is farther to the right on the periodic table.
Element 2 is more reactive because it does not have a valence shell close to the nucleus, so it will attract electrons.
Element 2 is more reactive because it does not have a full valence shell, so it will attract electrons.

Answer 1

Element 2 is more reactive because it does not have a full valence shell.

Element 1 has a 2,8 configuration (a full outer octet, like a noble gas) and is stable/inert. Element 2 has 6 valence electrons (2,8,18,18,6) and will tend to attract/gain electrons to complete its octet, so it is more chemically reactive.