Metals lose electrons under certain conditions to attain a noble-gas electron configuration. how many electrons must be lost by the element mg?

Explanation:

It is known that metals are the species which easily lose an electron to acquire stability.

For example, atomic number of magnesium is 12 and its electronic distribution is 2, 8, 2.

Hence, in order to attain stability it will readily lose two electrons. As a result, it will form ions.

Thus, we can conclude that 2 electrons must be lost by the element Mg.

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.