. Does a more negative heat of formation (a larger negative number) mean that a compound is more stable or less stable than an isomer with a less negative heat of formation

See explanation

Explanation:

Heat of formation, also called standard heat of formation, enthalpy of formation, or standard enthalpy of formation, the amount of heat absorbed or evolved when one mole of a compound is formed from its constituent elements, each substance being in its normal physical state (gas, liquid, or solid)(Encyclopedia Britannica).

The greater the magnitude of the negative value  of the heat of formation(the more negative), the greater stability of the compound formed. Hence, a more negative heat of formation (a larger negative number) means that a compound is more stable than an isomer with a less negative heat of formation.

we need the questions , i may then you.