What is the symbol (including the atomic number, mass number, and element symbol) for the nitrogen isotope with 8 neutrons? Express your answer as an isotope with stacked prescripts.

The isotope is represented as

Explanation:

General representation of an element is given as:

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

Atomic number is defined as the number of protons or number of electrons that are present in an atom.

Atomic number = Number of electrons = Number of protons  = 7 (for nitrogen)

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons = 7+8 = 15

Thus the isotope is represented as

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.