What group of elements on the periodic table are very reactive and why?

Answer 1

Group 1 elements are most reactive. The want desperately to have an octet of electrons but they have 1 too many (or 7 too few depending on how you look at it). And they will do anything to ionize to get that octet. They also get more reactive the larger they get. This is why the smaller halogens which lack a single electron (they are pretty reactive too) are not quite as reactive and why K is more reactive than Na. (NB: Atoms get larger moving down a group and smaller moving from left to right across a period).

Answer 2

The alkali metals (Group 1) are very reactive because they have only one electron in their outermost shell, making it easy for them to lose it to achieve a stable electron configuration. This reactivity increases down the group due to the decreasing ionization energy and increasing atomic size.

Answer 3

Group 17 is the most active, also called the halogen family. The reason because they are reactive is because they have seven valence electrons.

Answer 4

The alkali metals and the halogens are the most reactive because they only need to lose/gain one electron, respectively, to have a full valence (ie a noble gas configuration).

Answer 5

Alkali and alkaline earth metals placed at extreme left are very fast reactive as they have low ionization energy and they can easily loose their outermost electrons.