Question

: What is the formula weight of $Mg{{(Br{{O}_{4}})}_{2}}$?

Answer 1

The given compound in the question is $Mg{{(Br{{O}_{4}})}_{2}}$ and this compound is called magnesium perbromate, which there are 11 atoms involved in the formation of this molecule, i.e., one magnesium atom, two bromine atoms, and eight oxygen atoms.

Complete answer:
Formula mass or Molecular mass is the mass of the molecule that is formed with similar or different types of atoms. Each atom in the periodic table has an atomic number and atomic mass. This atomic mass is used to calculate the molecular mass of the molecule.
The given compound in the question is $Mg{{(Br{{O}_{4}})}_{2}}$ and this compound is called magnesium perbromate, which there are 11 atoms involved in the formation of this molecule, i.e., one magnesium atom, two bromine atoms, and eight oxygen atoms.
So, by adding the atomic mass of these atoms we can find the molecular mass. The atomic mass of Magnesium is 24.305, the atomic mass of oxygen is 15.999, and the atomic mass of bromine is 79.904.
We have to add this mass in the number of atoms ratio present in the molecule.
Molecular mass = atomic mass of magnesium + 2 (atomic mass of bromine + 4 x atomic mass of oxygen)
Molecular mass = 24.305 + 2 (79.904 + 4 x 15.999)
Molecular mass = 24.305 + 159.80 + 127.96
Molecular mass = 312.08
So, the formula or molecular mass of $Mg{{(Br{{O}_{4}})}_{2}}$ (magnesium perbromate) is 312.08.

Note:
Don’t forget to multiply the number of each atom present in the molecule. If you don’t remember the exact mass of the atoms, then the atomic mass of magnesium will be 24, the atomic of oxygen will be 16, and the atomic mass of bromine will be 80.