Question

The element ${\text{Ga}}$ has how many valence electrons?

Answer 1

For calculating the number of valence electrons of any element you have to know about the atomic number of that element because the atomic number of any element is equal to the number of protons or number of electrons present in that atom.

Complete step by step answer:
Valence electrons are those electrons which are present on the outermost shell of the atom and for counting that we will follow following data:
- In the periodic table element Gallium (${\text{Ga}}$) is located at ‘IIIA’ group in the p – block of the periodic table and it is denoted as ${}_{{\text{31}}}^{70}{\text{Ga}}$.
- Upper quantity which is mention in ${}_{{\text{31}}}^{70}{\text{Ga}}$describes the Atomic mass (${\text{A}}$) and lower quantity describes the Atomic number (${\text{Z}}$) of the gallium element.
- As we know that relation between Atomic number (${\text{Z}}$) and number of electrons are as follow:
Atomic Number (${\text{Z}}$) = No. of electrons = No. of protons
So that in gallium (${\text{Ga}}$) $31$ electrons are present as the atomic number of gallium is also $31$.
-Now electronic configuration of Gallium is shown as $\left[ {{\text{Ar}}} \right]{\text{4}}{{\text{s}}^{\text{2}}}{\text{3}}{{\text{d}}^{{\text{10}}}}{\text{4}}{{\text{p}}^{\text{1}}}$ and from this it is clear that in the outermost shell (4) three electrons are present.
Hence, in the element Gallium (${\text{Ga}}$) three valence electrons are present.

Note: Here some of you may do wrong calculation if you will count ten electrons of p- orbital also, so avoid that type of mistake and only count electrons of shell 4.