Question 6.
Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with explanation.
7N, 6C, 8O, 5B, 13A1
Which is the most electronegative element among these?
Answer:
Electronic configuration:
⇒ The atomic number of nitrogen = 7
The electronic configuration of 7N = 2,5
⇒ The atomic number of carbon = 6
The electronic configuration of 6C = 2,4
⇒ The atomic number of oxygen = 8
The electronic configuration of 8O = 2,6
⇒ The atomic number of boron = 5
The electronic configuration of 5B = 2,3
⇒ The atomic number of aluminum = 13
⇒ The electronic configuration of 13Al = 2,8,3
Among the given elements, oxygen is the most electronegative element.
Explanation: Electronegativity is the ability of an atom to attract shared pair of electrons.
⇒ Electronegativity increases as we move from left to right in a period.
⇒ Electronegativity decreases as we move down the group.
⇒ By combining these two facts, oxygen is the most electronegative element.
Note:
Electronegativity increases along a period because-
⇒ The atomic radius goes on decreasing as we move from left to right due to which the attraction between the outer electrons and nucleus increases.
Electronegativity decreases along a group because-
⇒ The atomic radius goes on increasing as we move from top to bottom due to which the attraction between the outer electrons and nucleus decreases.
