Sodium and chlorine reacting to form an ionic compound sodium chloride

What happens when sodium and chlorine atoms react?

Sodium has one electron in its outer shell. Chlorine has seven electrons in its outer shell. When they react sodium loses an electron to become a sodium ion with a charge of +1. Chlorine atoms accept an electron to become chloride ions with a charge of -1. After reacting the sodium and chloride ions have a full outer shell of electrons. A full outer shell of electrons is a stable arrangement. The inert gasses in group 18 of the periodic table all have a full outer shell and characteristically are very unreactive (they don’t easily combine with other elements). The new substance sodium chloride is made up of ions. Compounds that have ions bonded together are called ionic. The ions are held together by powerful electrostatic forces. Ionic compounds typically have high melting and boiling points as a consequence.

Homework… how much of this do you understand?

Watch the video especially the bit that deals with the changes to sodium and chlorine atoms when they react with each other. Magnesium has two electrons in its outer shell and it burns in chlorine gas like sodium.
Draw sodium and chlorine atoms and show how ions are produced when they react.
What are the charges of the ions?
what is the formula of magnesium chloride?

NCEA level 1 Science: Shelley Dudley’s class and ions.

You have learned a lot about ions recently. How much do you remember from Friday’s lesson?

1. Reacting sodium with chlorine: electron transfer and turning atoms into ions


Electrolysis of copper chloride: turning ions back into atoms

with electrical energy supplied by a power pack.



Some questions for experts.

We talked briefly about oxidising agents. When elements burn in oxygen we say they have become oxidised.

Magnesium burning in air.

                       2Mg + O2 —-> 2MgO

We say that magnesium has been oxidised to magnesium oxide

Magnesium also burns in chlorine

                       2Mg + CL2 —-> MgCL2

Why do we say that magnesium has been oxidised to magnesium chloride?

………and some links to related chemistry.

the thermite reaction

the reactivity series

balancing chemical equations and reactions of metals with acids

writing chemical formulae

View My Stats