How many electrons should Nitrogen (N) have around its Lewis dot model?

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.

Electrons are emitted

Hello.the answer is  hydrosphere, geosphere, and biosphere  have a nice day