Explanation:
Metals are the substances which tend to lose their valence electrons in order to attain stability.
For example, metals of group 1 are lithium, sodium, potassium, rubidium and cesium.
And, each of these elements have only 1 valence electron present. So, it is much easier to lose just one electron rather than losing 2 or 3 valence electrons.
Hence, alkali metals are the most reactive substances of the periodic table and they are present at extreme left side of periodic table.
Therefore, we can conclude that the most reactive metals are located at the extreme left of the periodic table.
