Ionic BondingIonic Bonding

What makes an atom most stable?What makes an atom most stable?

Electron configurationElectron configuration – –

When the highest occupied energy level is filled When the highest occupied energy level is filled with electrons the atom is stable, and probably will with electrons the atom is stable, and probably will not react chemicallynot react chemically

Electron Dot DiagramsElectron Dot Diagrams(Lewis Structures)(Lewis Structures)

Show valence electrons onlyShow valence electrons only Easy way to see if an atom is stable, and how Easy way to see if an atom is stable, and how

it may react to transfer electronsit may react to transfer electrons

OCTET RULEOCTET RULE Elements become happy when they have a Elements become happy when they have a

complete outer shell. They are usually happy complete outer shell. They are usually happy when the closest outer shell has 8 or 2 in the when the closest outer shell has 8 or 2 in the case of Helium.case of Helium.

In order to do this they will either lose or gain In order to do this they will either lose or gain electrons.electrons.

Ion formationIon formation If an atom has If an atom has greatergreater than 4 valences than 4 valences

electronselectrons Will Will gaingain enough to make 8 (octet rule) enough to make 8 (octet rule) Becomes negatively charged ion (anion)Becomes negatively charged ion (anion) This applies to elements in groups 5, 6, and 7This applies to elements in groups 5, 6, and 7P S Cl N F BrP S Cl N F Br

Ion formationIon formation If an atom has If an atom has lessless than 4 valence electrons: than 4 valence electrons:

It will It will loselose those outer electrons those outer electrons Becomes positively charged (cation)Becomes positively charged (cation) This applies to elements in Groups 1, 2, and 3This applies to elements in Groups 1, 2, and 3 Write the symbol and charge of the following.Write the symbol and charge of the following. Ca Na K Li Al BCa Na K Li Al B

Ionic bondsIonic bonds Once positive or negative ions are formed, Once positive or negative ions are formed,

they are attracted to each otherthey are attracted to each other

They form a chemical bond known as an ionic They form a chemical bond known as an ionic bond – bond – the force that holds cations and anions the force that holds cations and anions together; results from together; results from

transferred electronstransferred electrons

Oxidation Number vs. SubscriptsOxidation Number vs. Subscripts Ionic bonding is when two ions of opposite charge Ionic bonding is when two ions of opposite charge

attract and bond to each other forming an ionic attract and bond to each other forming an ionic compound. Consider the following examples of compound. Consider the following examples of formulas for ionic compounds.formulas for ionic compounds.

One NaOne Na+ + (sodium ion(sodium ion)(METAL)(METAL) and one Cl) and one Cl-- (chloride ion(chloride ion)(Non-metal)(Non-metal) bond to make NaCl ) bond to make NaCl (sodium chloride)(sodium chloride)

One Mg One Mg 2+ 2+ (magnesium ion) and two F (fluoride ions) (magnesium ion) and two F (fluoride ions) bond to make MgFbond to make MgF2 2 (magnesium fluoride)(magnesium fluoride)

The number at the top is the The number at the top is the oxidation numberoxidation number. . Once Once they combine you have a they combine you have a subscriptsubscript that tells how that tells how many of each type of atom are present. many of each type of atom are present.

MgMg33NN22

IONIC COMPOUND NAMINGIONIC COMPOUND NAMING Compounds that contain ions.Compounds that contain ions. Written using chemical formulasWritten using chemical formulas Rules are:Rules are:

STEP 1STEP 1 STATE THE STATE THE CATIONCATION FIRST (THE FIRST (THE

NAME OF THE FIRST ELEMENT) NAME OF THE FIRST ELEMENT) METALSMETALS

STEP 2STEP 2 DROP THE ENDING OF THE NAME DROP THE ENDING OF THE NAME

OF THE OF THE ANIONANION (THE SECOND (THE SECOND ELEMENT LISTED) AND ADD ELEMENT LISTED) AND ADD “IDE “IDE NON-METALSNON-METALS