The atomic mass of the metal.(M) = 51 g/mol
Further explanation
Given
32% of oxygen
Required
the atomic mass of the metal.
Solution
An oxide of trivalent metal : M₂O₃(Ar O = 16 g/mol)
The molar mass of metal oxide = 2M+16.3=2M+48
32% of oxygen, then :
32% x 2M+48 = 48
0.32(2M+48)=48
0.64M+15.36=48
0.64M=32.64
M=51