What are the valence electrons? For s-block and p-block elements show that number of valence electrons is equal to its group number.
What are the valence electrons? For s-block and p-block elements show that number of valence electrons is equal to its group number.
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- Electrons present in the outermost shell of the atom of an element are called valence electrons.
- 3Li is an s-block element and its electronic configuration is 1s22s1. Since it has one valence electron, it is placed in group 1.
- Therefore, for s-block elements, group number = number of valence electrons.
- However, for p-block elements, group number = 18 – number of electrons required to attain complete octet.
- 7N is a p-block element and its electronic configuration is 1s22s22p3. Since it has five electrons in its valence shell, it is short of three electrons to complete its octet.
- Therefore, its group number = 18 – 3 = 15.
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