The negative (oxygen) end of water is attracted to the positive sodium ion in the salt, extracts it from the lattice and more water molecules surround it (i.e. dissolve it). The same is true for the positive (hydrogen) end of water and the negative chloride ion in the salt.
According to nitrogen's electron configuration table, an atom of nitrogen contains two electrons in its first energy level (both in the s sub-shell) and five electrons in its second energy level (two in the s sub-shell and three in the p sub-shell). A more accurate Bohr model of a nitrogen atom could look like this: In the refined Bohr model, a nitrogen atom has a central nucleus, composed of seven protons and seven neutrons, surrounded by seven electrons.
This image is part of the sequence science and technology: simple electron configurations of the elements. Credit: SCIENCE PHOTO LIBRARY. Caption: Gold (Au). Diagram of the nuclear composition and electron configuration of an atom of gold-197 (atomic number: 79), the most common isotope of this element. The nucleus consists of 79 protons (red) and 118 neutrons (blue). 79 electrons (green) bind to the nucleus, successively occupying available electron shells (rings).