Question

The atomic numbers of elements P, Q, R, S and T are given below.

Element P Q R S T

Atomic number 7 10 12 4 19

From the above table, answer the following questions.

(a) Which element among these is a non-metal ?

(b) Which element belongs to 3rd period of periodic table ?​

Answer 1

) w is the noble gas having atomic number 10 and configuration (2,8)

(ii) x, y and z are the s block elements. They have 2,2 and 1 electrons in their outermost shell respectively.

(iii) Atomic size decreases across the period and increases down the group. Element z is having more atomic size

Answer 2

The answers to the following questions are:

(a) The elements P (7) and Q (10) among these are non-metals.

- The element P is Nitrogen and Q is Neon.

- Both of these are non-metals.

- All the other elements (R, S and T) are metals.

(b) The element R (12) belongs to the 3rd period of periodic table.

- The element R is Magnesium.

- It belongs to the 2nd group and 3rd period of the periodic table.