Answer:
Mn
Explanation: 4th shell so 4th row and count 7 from the left most column
This question is purely balancing the chemical equation where the number of atoms in reactants is equal to the number of atoms in products.
For the mentioned equation:
In the reactants, we have 2 atoms of Hg and 2 atoms of oxygen.
In the products, we should have 2 atoms of Hg and 2 atoms of oxygen.
Since the oxygen molecule is composed of 2 oxygen atoms, therefore the coefficient should be equal to 1 for the equation to be balanced.
An electron dot diagram shows an atom's number of valence electrons
The answer is b_______________\\\