CBSE Notes, Lectures

CBSE - Chemistry - Periodic Classification of Elements

Periodic Classification of Elements

NCERT Exercise

Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 
of the Periodic Table. Write the electronic configuration of these two elements. 
Which of these will be more electronegative? Why?

Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15  of the Periodic Table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?

Element

K L M

Nitrogen

Phosphorus

2 5

2 8 5

Nitrogen is more electronegative than phosphorus. On moving down a group, the number of shell increases. Therefore, the valence electrons move away from the nucleus and the effective nuclear charge decreases. This causes the decrease in the tendency to attract electron and hence electronegativity decreases.

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