Write the reaction as a CO2 + b H2O → c C6H12O6 + d O2 where a, b, c, and d are meant to be integers adjusted so that the number of each kind of atoms balance on each side. For this reaction, we have three kinds of atoms that must balance: carbon (C), hydrogen (H), and oxygen (O). Write three equations for a, b, c, and d that, if satisfied, will guarantee that the number of atoms of each kind are the same on each side of the reaction.

a = 6, b = 6, c = 1 and d = 6

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Explanation:

a CO₂ + b H₂O → c C₆H₁₂O₆ + d O₂

In the balance for Carbon (C)

a = 6c

In the balance for Oxygen (O)

2a + b = 6c + 2d

In the balance for Hydrogen (H)

2b = 12 c

b = 6c

To solve, we bring the equations together

a = 6c (eqn 1)

2a + b = 6c + 2d (eqn 2)

b = 6c (eqn 3)

Substituting for b and a in (eqn 2)

2a + b = 6c + 2d

2(6c) + 6c = 6c + 2d

12c + 6c = 6c + 2d

2d = 12c

d = 6c

Let c = 1

a = 6c = 6

b = 6c = 6

d = 6c = 6

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."