Why are elements H, Li, Na and K placed in group 1 ?

The element with atomic number 35 lies in group

Why alkali metals are placed in group 1 A, why they are named so?

Na and Li are placed in dry air. We get:

Why are sodium (Na) and potassium (K) placed in the same group of the pariodic table? Give any two reaons?

The densities of Li, Na and K followed the order

The densities of Li, Na and K followed the order

Group 2 elements are denser and harder than group 1 elements. Why ?

Name or state with reference to the elements of the modern periodic table. The element, from the elements Li, Na, K, having the least number of electron shells.

Consider the following elements: Be, Li, Na, Ca,K. Name the elements of same group .