Question

A metal M forms an oxide having the formula M2O3. It belongs to 3rd period in the modern periodic table. Write the atomic number and valancy of the metal.​

Answer 1

Answer:

The formula $M_2O_3$ indicates that the valency of the metal 'M' is 3. It has three valence electrons and belongs to group 15. Since it is present in third period, the element is aluminium(Al). The formula of the oxide is $Al_2O_3.$