10.Give the name of the second least reactive metal in group 1

The second least reactive metal in Group 1 of the Periodic Table is Sodium (Na).

Here's the step-by-step reasoning:

1. Group 1 elements of the Periodic Table are known as Alkali Metals. This group includes Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr).

2. The reactivity of Alkali Metals increases as you go down the group. This is because the outermost electron is more easily lost as it's further from the nucleus, making the atom more reactive.

3. Therefore, the least reactive metal in this group is at the top, which is Lithium.

4. The second least reactive, then, is the next one down: Sodium.