In terms of electrons in the periodic table why are group 1 metals very reactive and group 7 non-metals very reactive too?

Answer 1

Atomic elements typically want to have full electron shells ("valence shells"), instead of shells with uneven numbers.

Group 1 metals have only 1 electron in their valence shell, so they quickly react to lose this electron and have an empty shell (but a full shell underneath it).

Group 7 elements have 7 valence electrons and react quickly to steal another atom's electron and gain a full shell of 8 electrons.

This willingness to lose or steal electrons makes the elements very reactive, but in different ways. Group 1 elements will become positively charged ions, and Group 7 will become negatively charged. (Na+ versus Cl-)

Group 6 elements (such as oxygen) are also somewhat reactive and will steal 2 electrons to become even more negatively charged (O 2-)

Answer 2

Group 1 metals are very reactive because they have one electron in their outer shell, which they readily lose to achieve a stable electron configuration. Group 7 non-metals are very reactive because they are one electron short of a full outer shell, so they can easily accept an electron to achieve stability. This makes both group 1 metals and group 7 non-metals highly reactive in order to achieve a stable electron configuration.

Answer 3

It is not the groups that are reactive but the atoms. Atoms react because they contain an unstable number of electrons and by reacting can reach a more stable number of electrons.