Question

21. The atomic number of an element is 20. In which period of the modern periodic
table, could this element be placed? Why? How will you decide whether the
element is a metal or a non-metal?​

Answer 1

Explanation:

In the modern Periodic table this element belongs to group 2 and period 7.

This can be identified by its atomic no. and its electronic configuration.

As the electronic configuration of 20 will be (2,8,8,2) its valency is 2 and thus it belongs to group 2 and the no. of shells present are 4 n therefore it belongs to period 4.

As the elements placed towards the right-side or present in the s-block are metals.

therefore this element is a metal.

Answer 2

• In the modern Periodic table this element belongs to group 2 and period 4.
• This can be identified by its atomic no. and its electronic configuration.
• As the electronic configuration of 20 will be (2,8,8,2) its valency is 2 and thus it belongs to group 2 and the no. of shells present are 4 n therefore it belongs to period 4.
• As the elements placed towards the right-side or present in the s-block are metals,  therefore this element is a metal.