8/16/2019 Section 1f Ionic Compounds Guided Learning

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Section 1f: ionic compounds

Main ideas about ionic compounds

• When they react with each other some elements form ionic compounds to obtain noble gas electronic

configuration (i.e. a full outer shell).

• During a chemical reaction only valence electrons in the atoms are involved.

• During the formation of an ionic bond valence electrons are transferred between the reacting atoms.

• Metal atoms lose electrons.

• Non-metal atoms gain electrons.

Diagrams showing how the electron arrangement changes during the formation of an ionic bondbetween a sodium atom and a chlorine atom

Formation of sodium chloride from sodium and chlorine atoms

sodium atom chlorine atom

→

sodium ion chloride ion

protons

electrons

neutrons

charge

electronicconfiguration

Step 1 Draw an atomic diagram to the full electronic configuration for both the sodium and chlorine

atom, use the symbol of the element to symbolie the nucleus. !or each atom, write in thenumber of subatomic particles.

Step 2  Now you need to show the electron transfer that will occur between the sodium and chlorineatom. "se an arrow to show which valence electron (electron in most outer shell) will betransferred and in which direction.

Step 3 Draw on the product side what the sodium and chlorine particle loo# li#e after the electrontransfer from step $. %hells without electrons are not drawn.

Step 4 &omplete the number of subatomic particles for each new particle on the productside and calculate its charge. 'lace suare brac#ets around each sodium and chloride particleand write the charge on the outside of the right brac#et at the top. he particle inside he brac#etis called an ion.

What is an ion*

A shorter way of drawing the changes in electron arrangement.

Draw the same diagram as above again but with only the valence electrons in it.

What if the number of electrons lost is different from the number of electrons gained?

!or instance, an o+ygen atom needs to gain two electrons but a sodium atom only has one valenceelectron to give.

Idea he number of electrons lost or gained must be the same so that the overall positive charge is eualto the overall negative charge. he number of electrons transferred per atom determines the ratio in which

the atoms react.

"se a diagram showing the valence electrons only to show how you thin# sodium and o+ygen will react*

8/16/2019 Section 1f Ionic Compounds Guided Learning

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Now do the same for barium and chlorine, aluminium and chlorine, aluminium and o+ygen, aluminium and

nitrogen.