Ionic Bonds

An atom will bond with another atom in order to achieve stability, which means in order for both atoms to get complete outermost energy levels. One way a complete outermost energy level can be achieved is by the transfer of electrons from one atom to another. Bonding that involves a transfer of electrons is called ionic bonding. Ionic bonding, or electron-transfer bonding, gets its name from the word ion. An ion is a charged atom. Remember, an atom is neutral. But if there is a transfer of electrons, at neutral atom will become a charged atom.
Because ionic bonding involves the transfer of electrons, one atom gains electrons and the other atom loses electrons. Within each atom the negative and positive charges no longer balance. The atom that has gained electrons has gained a negative charge. It is a negative ion. For example, fluorine (F) has '7 valence electrons. To complete its outer~ most energy level, the fluorine atom gains 1 electron. In gaining 1 negatively charged electron, the fluorine atom becomes a negative ion. The symbol for the fluoride ion is F". (For certain elements, the name of the ion is slightly different from the name of the atom. The difference is usually in the ending of the names with the fluorine atom and the fluoride ion.)

The sodium atom (Na) has 1 valence electron. When a sodium atom loses this valence electron, it is left with an outermost energy level containing 8 electrons. In losing 1 negatively charged electron, the sodium atom becomes a positive ion. The symbol for the sodium ion is NA+.



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