Question

The valency of the aluminium is $3$. Write the valency of other radicals present in the following compounds.
Aluminium chloride

Answer 1

We have to know that in chemistry, periodic tables play a vital role. In the periodic table there are totally $118$ elements. In the periodic table there are totally $18$ columns and $7$ rows. The columns are called groups. Hence, $18$ groups in the periodic table. The rows are called periods. Hence, totally $7$ period in the table. Aluminium and chlorine are one of the elements in the periodic table. The symbol of Aluminium is ${\text{Al}}$. The symbol of chlorine is ${\text{Cl}}$.

Complete answer:
The molecular formula of aluminium chloride is ${\text{AlC}}{{\text{l}}_{\text{3}}}$.
We have to know that the valency of the atom is nothing but the number of electrons gain or loss to attain the stable electronic configuration in the molecule.
The valency of aluminium is$3$. Because aluminium atoms lose three electrons to attain the stable electronic configuration in aluminium chloride.
The other radical present in the aluminium chloride is chlorine. There are three chlorine atoms present in aluminium chloride. Each chlorine atom gains one electron to attain stable electronic configuration. Here three chlorine, that's the reason three electrons from aluminium atom each chlorine atom accept each electron and attain stable configuration.
Hence, the valency of chloride ion is $3$ .

Note:
We have to know that the atomic number of the element is nothing but the number of electrons or number of protons. The mass number of the atom is nothing but the sum of number of protons and the number of neutrons. The atomic number of Aluminium is $13$. The atomic number of chlorine is $17$. The mass number of Aluminium is $36.9$. The mass number of chlorine is $35.45$.