How are the group number and period number of an element in the periodic table determined from the electronic configuration of the element ?

Atomic number of few elements are given below 10, 20, 7, 14 (a) Identify the elements (b) Identify the group number of these elements in the periodic table (c) Identify the periods of these elements in the periodic table (d) What would be the electronic configuration for each of these elements (e) Determine the valency of these elements.

The number of elements in the 4th period of periodic table is

The elements of a group in the periodic table

Identify the group number of T hat(l) element in periodic table.

An element X belongs to group 17 and third period of the periodic table Write electronic configuration of the element. What is its valency?

Which elements constitute group 14 of periodic table? Write their electronic configuration.