Group 1 metals

This is a group of highly reactive metals also called the alkali metal series, and contains the metals Lithium, Sodium, Potassium, Rubidium, Cesium and Francium. Hydrogen is also a member of this group however, it shares both the properties of a group 1 metal and a group 7 non-metals. These metals possess 1 electron in their out electron shell as shown below:

The electronic configurations for the elements in group 1 are shown below:

Elements	Electronic configuration
Li – Lithium	2,1
Na – Sodium	2,8,1
K – Potassium	2,8,8,1

As stated before, all elements try to achieve the stable electronic configuration of the closest Nobel gases (filled outer shells) . Since the elements in this group posses 1 electron in their outer shell, they will achieve stability by losing its single electron to a non-metal during reactions. For example, Sodium has an electronic configuration of 2,8,1. The closest noble gas to sodium is neon which has a electronic configuration of 2,8. Sodium will thus lose its single electron to a non-metal to achieve this stability.

Please refer to the section on Atomic Structure if you are having difficulty understanding electronic configuration.

Reactivity increases with increased atomic size as it is easier to remove the outer electron with increased atomic size. This is so because the outer electrons are further away from the nucleus and there is a resulting loss of electrostatic forces of attraction which exists between the negatively charged electrons and the positively charged nucleus. With this in mind the order of reactivity is as a follows:

Li<Na<K<Rb<Cs<Fr

By now, we know there is an equal number of protons (+1 charge) and electrons (-1 charge). When one electron is lost from the group 1 metals there will be a surplus of positive charge which will be equal to the difference in the amount of protons vs. electrons. In the case of group 1 metals, there will be a +1 charge.

Positively or negatively charged atoms are called ions. Hence when group 1 metals react they result in a +1 positively charged ion.