An element with the valence electron configuration 4s24p4 would form a monatomic ion with a charge of fill in the blank 5 . In order to form this ion, the element will ___ electron(s) from/into the subshell(s).

Charge= -2.

Gains two electron into the 4p^4 to become 4p^6.

Explanation:

The element in the periodic table/chart that matches with the valence electron configuration is Selenium with full electron configuration of [Ar] 3d^10 4s^2 4P^4 which is a non-metal that is found in group 4 of the periodic table/chart.

Selenium can receive 2 more electrons on the 4p^4 to give a -2(minus 2) ion that is Se^2-.

Selenium can also loose 2 electron from 4s^2 to give a +2 ion that is Se^2+.

Selenium can also loose 2 electrons from 4s^2 and 2 electrons from 4p^4 to form Se^4+.

Selenium can also loose 2 electrons from 4s^2 and 4 electrons from 4p^4 to form Se^6+.

Thus, in order to form a monatomic ion with a charge(we will be making use of the most stable one). Thus, it will gain two more electron since this is easier to become 4s^2 4p^6.

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.