2.7 Ionic bonds are attractions between ions of opposite charge

1:1

An NaCI(sodium chloride) crystal can be of any size(there is no fixed number of ions), but sodium and chloride ions are always present in a ________ ratio. The ratio of ions can differ in the various kinds of salts.

Opposite charges attract. The positively charged sodium ions (Na+) and the negatively charged chloride ions (CI-) are held together by ionic bonds, attractions between oppositely charged ions.

Explain what holds together the ions in a crystal of table salt(NaCI)

Ion

Remember that electrons are negatively charged particles. The transfer of an electron moves one unit of negative charge from one atom to the other. Sodium, with 11 protons but now only 10 electrons, has a net electrical charge of 1+. Chlorine, having gained an ectra electron, now has 18 electrons but only 17 protons, giving it a net electrical charge of 1-. In each case, an atom has become an _____, an atom or molecule with an electrical charge resulting from a gain or loss of one or more electrons.(Note that the names of negatively charged ions often end in ide, such as chloride.)

Salt

Sodium Chloride is a familiar type of __________, a synonym for an ionic compound. __________ often exist as crystals in nature.

8

Table salt is an example of how the transfer of electrons can bond atoms together. The image below shows how a sodium atom(Na) and a chlorine atom(CI) can form the compound sodium chloride(NaCI). Notice how sodium only has 1 electron in its outer shell, whereas chlorine has 7. When these atoms interact, the sodium atom transfers its single outer electron to chlorine. Sodium now has only two shells, the second shell having a full set of 8 electrons. When chlorine strips away sodium's electron, its own outer shell is now full with _______ electrons.

Environment

The_________ affects the strength of ionic bonds. In a dry salt crystal, the bonds are so strong that it takes a hammer and chisel to break enough of them to crack the crystal. If the same salt crystal is placed in water, however, the ionic bonds break when the ions interact with the water molecules and the salt dissolves.

Ionic Bond

Two ions with opposite charges attract each other. When the attraction holds them together, it is called an ___________. The resulting compound, in the case of sodium chloride(NaCI), is electrically neutral.