Which of the equations below represents the correct balanced equation?
a. mg (s) + hcl (aq) --> mgcl2 (aq) + h2 (8)
b. mg (s) + 2hcl (aq) --> mgcl2 (aq) + h2 (8)
c. 2mg (s) + hci (aq) --> mgcl2 (aq) + h2 (8)
d. 2mg (s) + 2hcl (aq) --> mgcl2 (aq) + h2 (8)

b. Mg (s) + 2HCl (aq) --> MgCl2 (aq) + H2

Explanation:

A subscript applies only to the element it is attached to while coefficients apply to all elements in a compound.

"a" has 1 atom of each element on the left but 2 Cl on the right.

"c" has 2 Mg, 1 H, & 1 Cl on the left but 1 Mg, 2 H, and 2 Cl on the right.

"d" has 2 atoms of each element on the left but only 1 Mg on the right.

"b" is the only answer with equal numbers of atoms on the right and left sides of the equation.

the electronic configuration of an atom with eight electrons is 1s²2s²2p⁴. the orbital diagrams are shown in the figure.

as per the hunds rule:

1. electrons tend to avoid being in the same orbital as per as practicable.

2. electrons in different orbitals of the same energy will have their spin parallel.

this can be illustrated from the multiplicity of the orbitals of the atom. as there are four electrons in the p orbital and p orbital has 3 sub-shells. the electrons can be fed in different ways as shown in the figure but the correct orbital diagram will be as per the hunds rule.

a is the answer to this question

explanation: