Question
What are the atomic numbers of elements whose outermost electrons are represented by
- 3s1
- 2p3
- 3p5?
✓
Answer
- 3s1
Completing the electron configuration of the element as
1s2 2s2 2p6 3s1.
$\therefore$ Number of electrons present in the atom of the element
= 2 + 2 + 6 + 1 = 11
$\therefore$ Atomic number of the element = 11
- 2p3
Completing the electron configuration of the element as
1s2 2s2 2p3.
$\therefore$ Number of electrons present in the atom of the element = 2 + 2 + 3 = 7
$\therefore$ Atomic number of the element = 7
- 3p5
Completing the electron configuration of the element as
1s2 2s2 2p6 3s2 3p5 1s2 2s2 2p6 3s2 3p5
$\therefore$ Number of electrons present in the atom of the element = 2 + 2 + 6+2+5 = 17
$\therefore$ Atomic number of the element = 17
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