Answer:
5
Explanation:
The full electronic configuration of the element is
1s²2s²2p63s²3p³
The total number of electrons = addition of the index
That is number of electrons = 2+2+6+2+3 = 15
Therefore the atomic number of the element is 15.
Name of element with atomic number 15 is Phosphorus with symbol P
Number of electrons in the atom of the element is 15.
Using KLMN configuration = 2:8:5
Therefore number of valence electrons is 5
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