Respuesta :
It’s 2 because it’s the number of row it is in; the element is calcium in row 2
The correct answer is 2.
Valence electrons are the electrons present in the outermost shell of the atom.
Given electronic configuration:-
[tex]1s^{2} 2s^ 2 2p^ 6 3s^ 2 3p^ 6 4s^ 2[/tex]
From the above electronic configuration, the outermost shell is the fourth shell that is [tex]4s^ 2[/tex]. The number of electrons in this shell is 2.
Hence, the atom has 2 valence electrons.
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