Which group in the periodic table would have an an ion of a -2 charge?

Group 6

Explanation:

There are eight (8) groups in the periodic table. Elements in Group 6 include OXYGEN, SULPHUR etc.

These elements have an outermost shell with 6 electrons; thus, they are always ready to RECEIVE two electrons from possible donors to form a completely filled outermost shell.

For example

Oxygen has atomic number of 8, its configuration is 2, 6

Sulphur, has atomic number of 16, its configuration is 2, 8, 6

Each require TWO electrons to attain stable octet structure, so, will accept two electrons and become an ANION with -2 charge

O2 + 2e- ---> 2O-

S2 + 2e- ---> 2S-

it means there are 3 atoms of oxygen

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.