When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation

The correct answer is Option 1.

Explanation:

We are given two intermediate equations and a final net equation for the formation of calcium carbonate. To form a net equation, we have to apply some operations on the second equation.

Two intermediate equations given are:

To get the final equation, we will half the second equation and reverse the equation, we get:

Equation 1:      

Equation 2:      

Net Equation:    

Hence, the correct answer is Option 1.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.