Question

Write the electronic configuration of the first four elements in group 1???
Which similarity do you find in their configuration ??
How many valence electrons are there in each of these elements????

Answer 1

Hydrogen-1
Lithium-2,1
Sodium-2,8,1
Pottasium -2,8,8,1

Answer 2

Answer: The electronic configuration of the elements are given below.

Explanation:

First four elements present in Group 1 are Hydrogen, Lithium, Sodium and Potassium. The atomic number of these elements are 1, 3, 11 and 19 respectively.

To write the electronic configuration, we need to know the number of electrons which is equal to the atomic number of the element.

Electronic configuration of Hydrogen : $1s^1$

Electronic configuration of Lithium : $1s^22s^1$

Electronic configuration of Sodium : $1s^22s^22p^63s^1$

Electronic configuration of Potassium : $1s^22s^22p^63s^23p^64s^1$

From the above electronic configurations, we can say that the number of valence electrons of all the elements are same which is 1.

Valence electrons are defined as the number of electrons which are present in the outermost shell.