Describe how sodium and chlorine atoms are changed into ions when they react with each other to form sodium chloride, NaCl. What is the name given to this type of bonding? (At. No of sodium = 11; At. No. of chlorine = 17)
The atomic number of sodium is 11, so its electronic configuration is 2, 8, 1. Sodium atom has only 1 electron in its outermost shell. So, the sodium atom donates one electron (to a chlorine atom) and forms a sodium ion, Na+. The atomic number of chlorine is 17, so its electronic configuration is 2,8,7. Chlorine atom has 7 electrons in its outermost shell and needs 1 more electron to achieve the stable 8-electron inert gas configuration. So, a chlorine atom takes one electron (from the sodium atom) and forms a negatively charged chloride ion, Cl-. This type of bonding is called ionic bonding.