Question

How many electrons has an atom with atomic number 12?

Answer 1

Hint: First of all, write the electronic configuration of the atom by using the given atomic number and then, by using that we can find the number of the electrons present in the atom. Now you can easily answer the statement.

Complete answer:
- From the periodic table we come to know that the atom having the atomic number as 12 is magnesium.
- Magnesium is a metal which comes under the category of the alkaline earth elements and belongs to the s-block elements of the periodic table.
- It lies in the 2^nd group and 3^rd period of the periodic table.
- It has the atomic number as 12 and the mass number as 24 and has the electronic configuration as: ${{[Ne]}^{10}}3{{s}^{2}}$.

Now considering the statement as;
- The number of electrons present in an atom is always equal to the atomic number of that very element.
- And The electrons which are present in the outermost valence shell of an atom are called the valence electrons of the atom.
- From the electronic configuration of the magnesium atom, we come to know that the number of electrons present in the magnesium are 12 electrons (i.e. ten electrons plus the two electrons which are present in the 3s orbital).

Thus, the total number of electrons present in the magnesium is 12

Note: Magnesium being an alkaline earth metal has ten electrons in its outermost shell and has a strong tendency to lose the two electrons present in 3s orbitals to acquire the stable fully-filled electronic configuration and exhibits +2 oxidation state in its compounds.