WRITING AND NAMING IONIC COMPOUNDS. ATOMS COMBINE IN SIMPLE WHOLE NUMBER RATIOS TO BECOME MORE STABLE THE SMALLEST UNIT OF ATOMIC COMBINATIONS THAT RETAINS.

WRITING AND NAMING

IONIC COMPOUNDS

WRITING AND NAMING

IONIC COMPOUNDS

ATOMS COMBINE IN SIMPLE WHOLE NUMBER RATIOS TO BECOME MORE STABLE

THE SMALLEST UNIT OF ATOMIC COMBINATIONS

THAT RETAINS THE CHARACTERISTICS OF THE

COMPND IS A MOLECULE

THE COMPOSITION OF A MOLE-CULE CAN BE REPRESENTED IN TWO WAYS AS AN EMPIRICAL OR A MOLECULAR FORMULA

AN EMPIRICAL FORMULA EXPRESSES THE SIMPLEST

RATIO OF ATOMS IN A COMPOUND

CH2

THE COMPOSITION OF A MOLE-CULE CAN BE REPRESENTED IN TWO WAYS AS AN EMPIRICAL OR A MOLECULAR FORMULA

A MOLECULAR FORMULA TELLS HOW MANY OF

EACH ATOM ARE PRESENT IN THE COMPND

C3H6

THE COMPOSITION OF A MOLE-CULE CAN BE REPRESENTED IN TWO WAYS AS AN EMPIRICAL OR A MOLECULAR FORMULA

A REMARKABLE FEATURE OF COMPOUNDS FORMED FROM ELEMENTS IS THAT THE PROPERTIES OF THE REACTANT ELEMENTS IS LOST

+

WHEN AN ATOM LOSES OR GAINS ELECTRONS IN ORDER TO ACHIEVE ITS OCTET IT FORMS AN ION

THERE ARE ALSO COMBINATIONS OF ATOMS THAT HAVE AN IONIC CHARGE A.K.A. POLYATOMIC IONS

POLY- MEANS MANY, BUT WE TREAT EACH OF

THESE POLYATOMIC IONS AS A SINGLE UNIT WITH A

SINGLE CHARGE

TODAY IS ALL ABOUT COMBINING THESE ELECTRICALLY CHARGED IONS TOGETHER TO FORM STABLE COMPOUNDS.

REMINDER: WHEN TWO ATOMS COMBINE

TRANSFERRING VALENCE ELECTRONS IT IS CALLED

AN IONIC BOND.

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AN IMPERFECT ATOM

I WANTI WANTTO BETO BE

PERFECT!PERFECT!

I WANTI WANTTO BETO BE

PERFECT!PERFECT!

IT COULD LOSE AN

ELECTRON!

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WHAT DOES SODIUM NEED TO DO TO BECOME LIKE

NEON?

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WHAT DOES SODIUM NEED TO DO TO BECOME LIKE

NEON?

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IT COULD LOSE AN

ELECTRON!

WHAT DOES SODIUM NEED TO DO TO BECOME LIKE

NEON?

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NOW SODIUMIS MORE STABLE!

11 p’s-10 e’s

+1 charge

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--I WANTI WANT

TO BETO BEPERFECT!PERFECT!

I WANTI WANTTO BETO BE

PERFECT!PERFECT!

AN IMPERFECT ATOM

IT COULD GAIN AN

ELECTRON!

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WHAT DOES Cl NEED TO DO TO BECOME LIKE A NOBLE GAS,

LIKE Ar?

-IT COULD GAIN AN

ELECTRON!

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WHAT DOES Cl NEED TO DO TO BECOME LIKE A NOBLE GAS,

LIKE Ar?

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IT COULD GAIN AN

ELECTRON!

WHAT DOES Cl NEED TO DO TO BECOME LIKE A NOBLE GAS,

LIKE Ar?17 p’s-18 e’s

-1 charge-1 charge

SO WHAT’S THE BOTTOM LINE?

AN ATOM WILL SHARE, LOSE OR GAIN ENOUGH

ELECTRONS TO BECOME MORE STABLE WITH 8

ELECTRONS IN ITS OUTERMOST ENERGY LEVEL.

AND THEN IT WILL BOND WITH ANOTHER ATOM OF A

DIFFERENT ELEMENT.

THINK ABOUT IT…FROM OUR PREVIOUS

EXAMPLE SODIUM HAD AN EXTRA ELECTRON AND GAVE IT

AWAY TO CHLORINE, WHICH WAS IN NEED OF ANOTHER

ELECTRON.THIS FORMED A BRAND NEW COMPOUND, NaCl IN WHICH

BOTH ELEMENTS WERE MORE STABLE

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AN ELECTRON IS TRANSFERRED FROM THE Na

ATOM TO THE Cl ATOM

AN ELECTRON IS TRANSFERRED FROM THE Na

ATOM TO THE Cl ATOM

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BOTH ATOMS ARE HAPPY, THEY BOTH HAVE 8

ELECTRONS IN THEIR OUTERMOST ENERGY LEVEL. THIS

IS AN IONIC COMPOUND

OPPOSITELY CHARGED IONS ATT-RACT EACH OTHER AND FORM AN IONIC BOND THAT IS ELECTRICALLY NEUTRAL,

LOOKING AT THE STRUCTURE OF SALT SHOWS THAT THE

ATTRACTION BETWEEN IONS IS SO GREAT THAT MANY

SODIUM AND CHLORIDE IONS BECOME INVOLVED

THE SMALLEST STACK OF THESE ANIONS AND CATIONS

IS CALLED A UNIT CELL.

UNIT CELLS ARE STACKED TOGE-THER TO MAKE UP A CRYSTAL LATTICE.

CATIONS & ANIONS ARE PULLED TOGETHER IN A TIGHTLY PACKED STRUCTURE, WHICH GIVES IT A DISTINCTIVE STACKED SHAPE

PROPERTIES OF IONIC COMPOUNDS

CAN CONDUCT

ELECTRICITY

WHEN MELTED IT FREES UP THE IONS TO MOVE PAST EACH OTHER

PACK IN HIGHLY

ORDERED ARRANGEME

NTS

IONS IN A SALT FORM

REPEATING PATTERNS CALLED A CRYSTAL LATTICE

PROPERTIES OF IONIC COMPOUNDS

HARD

PACKED INTO LAYERS, TAKES A

LOT OF ENERGY TO BREAK ALL OF THE

BONDS

BRITTLE

IF A FORCE IS STRONG ENOUGH TO REPOS-ITION A LAYER THEN THE

REPULSIVE FORCES DRIVE IONS APART

PROPERTIES OF IONIC COMPOUNDS

HIGH MELTING

POINTS AND BOILING POINTS

BECAUSE OF STRONG ATTRA-CTION BETWEEN IONS, IT TAKES A LOT OF ENERGY TO BREAK THEM

APART

WE CAN PREDICT THE COMBINATIONS OF IONS AND THE FORMATION OF THEIR IONIC FORMULAS,

KNOWING HOW IONS INTERACT

PREDICTING THE FORMATION OF IONIC CMPNDS

WE CAN HAVE 2 DIFFERENT KINDS OF IONIC COMPOUNDS FORMED: BINARY OR TERNARY

THERE ARE A COUPLE OF RULES TO FOLLOW TO MAKE SURE THAT THE

PROPER IONIC FORMULA IS WRITTEN.

WRITING IONIC FORMULAS

RULE #1 IONS WILL COMBINE IN SMALL WHOLE NUMBER

RATIOS THAT ADD TO GIVE A NEUTRAL COMPOUND.

THE IONS’ CHARGES MUST ADD UP TO ZERO

IT’S BETTER TO BE POSITIVE THAN

NEGATIVETHE POSITIVE ION IS ALWAYS WRITTEN

FIRST.

RULE #2

SOME IONIC COMPNDS AUTOMATICALLY HAVE

CHARGES THAT ADD UP TO ZERO.

WHAT IF WE WERE FORMING IONIC

COMPOUNDS WITH IONS WHOSE CHARGES DIDN’T ADD UP TO A CHARGE OF

EXACTLY 0?HOW DO WE DECIDE THE

RATIO OF THE IONS?

WHAT IF WE HAD THREE CHLORINE IONS?

IT WILL TAKE 3 Cl-1 IONS TO EQUAL ONE Al+3 ION.

WE HAVE A TRICK THAT WILL HELP US KNOW THE NUMBER OF THE

IONS TO MAKE A NEUTRAL COMPOUND.IT’S NOT A TRICK SO MUCH AS A SHORTCUT!

CRISS-CROSS RULE:

TO WRITE THE FORMULAS FOR COMPOUNDS

CONTAINING POLYATOMIC IONS, FOLLOW THE RULES FOR WRITING FORMULAS

FOR BINARY COMPOUNDS, WITH ONE EXTRA CONSIDERATION.

USING POLYATOMIC IONS

WRITE PARENTHESES AROUND THE GROUP REPRESENTING THE

POLYATOMIC ION WHEN MORE THAN ONE OF THE

ION IS NEEDED TO DEVELOP THE PROPER

RATIO.

USING POLYATOMIC IONS

MOST OF THE TIME YOU CAN NAME AN IONIC COMPOUND BY

1) WRITING THE NAME OF THE FIRST ELEMENT

2) WRITING THE ROOT OF THE NAME OF THE SECOND ELEMENT

3) ADDING -IDE TO THE ROOT

NAMING THEM

NAMES OF NEGATIVE IONSPARENT ELEMENTPARENT ELEMENT NEGATIVE IONNEGATIVE ION

CHLORINECHLORINE CHLORIDECHLORIDE

OXYGENOXYGEN OXIDEOXIDE

NITROGENNITROGEN NITRIDENITRIDE

PHOSPHORUSPHOSPHORUS PHOSPHIDEPHOSPHIDE

FLUORINEFLUORINE FLUORIDEFLUORIDE

IODINEIODINE IODIDEIODIDE

SULFURSULFUR SULFIDESULFIDE

BROMINEBROMINE BROMIDEBROMIDE

NAMING THEMCaCl2

K3P

Al2S3

Calcium chloride

Potassium phosphide

Aluminum sulfide

SOME OF OUR METALS HAVE MORE THAN ONE IONIC CHARGE1) WE HAVE TO FIGURE OUT WHICH CHARGE THE METAL HAS2) THEN WE DESIGNATE THAT PARTICULAR METAL WITH A ROMAN NUMERAL

NAMING THEM

FeCl2

FeCl3

PbBr2

Iron(II) chloride

Iron (III) chloride

Lead (II) bromide

NAMING THEM

IF THE COMPOUND HAS A POLYATOMIC ION IN IT1) NAME THE FIRST ELEMENT2) THEN NAME THE POLYATOMIC ION

NAMING THEM

Fe(OH)2

Ca3 (PO4)2

Na2SO4

Iron(II) hydroxide

Calcium phosphate

Sodium sulfate

NAMING THEM

BONDING & BOND ENERGIES THERE IS A LARGE AMOUNT

OF ENERGY STORED IN THE BONDS OF AN IONIC COMPOUND (INDICATION OF STABILITY).THEREFORE, IT TAKES A

LOT OF ENERGY TO PULL THE TWO IONS APART

ONCE THEY HAVE ESTABLISHED THEIR

OCTETS AND HAVE BONDED (BOND ENERGY)

THIS LATTICE ENERGY GIVES US A METHOD OF MEASURING THE BOND STRENGTH IN IONIC COMPOUNDS.

THE LATTICE ENERGY IS THE ENERGY RELEASED TO

FORM A BOND, AND IS EXACTLY EQUAL TO THE

BOND ENERGY, WHICH IS THE ENERGY TO BREAK A

BOND.