3. An element has its electronic configuration as 2, 8, 2. Now answer the following questions.

a. What is the atomic number of this element?

Answer. The atomic number of this element is 2 + 8 + 2 = 12.

b. What is the group of this element.

Answer. The electronic configuration of the given element is 2, 8. 2 which shows that this element has 2 valence electrons. Hence the given element is placed in group 2.

c. To which period does this element belong?

Answer. The electronic configuration of the given element is 2, 8, 2 which shows that the electrons are arranged in 3 shells. Hence the given element is placed in third period.

d. With which of the following elements would this element resemble?

(Atomic numbers are given in the brackets) N (7), Be (4) , Ar (18), Cl (17).  

Answer. Electronic Configuration:

N (7) – 2 , 5         Be (4) – 2, 2 Ar (18) – 2 , 8, 8    Cl (17) – 2, 8, 7

The element Beryllium (Be) has valence electron 2 just like the given element. Hence this element will be chemically similar to the given element which has the same number of valence electrons in its atoms.