Explain why H can be placed in gr-1 and gr-17 in the periodic table.

Find the atomic number of an element which belongs to third period and group-17 in the periodic table.

Hydrogen can be placed in Group 17 instead of Group 1 of periodic table. Give reason.

Using the aufbau principle in which block can k (z = 19) be placed in the periodic table?

Hydrogen can be placed in Group 17 instead of Group 1 of periodic tabic. Give reason.

Explain how the elements are arranged in the form of the periodic table.

Explain why, the properties of elements are repeated 2,8,18 and 32 elements in the periodic table.

Write the reasons in favour of placing hydrogen in group VIIA of the periodic table.

Write the reasons in favour of placing hydrogen in grou pIA of the periodic table.

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

Explain why the metals placed above hydrogen in the electrochemical series are not available in nature in the free state.