Ionic Ionic CompoundsCompounds::

TransferTransfer of electrons of electrons are made up of positive and negative ionsare made up of positive and negative ions

– All of the positives and negatives organize All of the positives and negatives organize nicely.nicely. Negative-positive attractNegative-positive attract Negative-negative and positive-positive repelNegative-negative and positive-positive repel

– Ionic compounds form fromIonic compounds form from the inside-out as solid crystalsthe inside-out as solid crystals

Salt, NaCl

4.2 – Ionic and Covalent Compound Naming4.2 – Ionic and Covalent Compound Naming

Covalent Covalent MoleculesMolecules::

shareshare electrons. electrons.– These molecules clump together as These molecules clump together as

solids, liquids or gasessolids, liquids or gases

Covalent molecules are like a play-pit Covalent molecules are like a play-pit full of plastic ballsfull of plastic balls Each plastic ball = 1 covalent molecule Each plastic ball = 1 covalent molecule

of Hof H22OO Pit full of balls = swimming pool full of Pit full of balls = swimming pool full of

waterwater

Water, HWater, H22OO

Naming Ionic Compounds:Naming Ionic Compounds:

Ionic compounds are composed of Ionic compounds are composed of cationscations and and anionsanions..– name of an ionic compound = cation name of an ionic compound = cation

anionanion-ide-ide– Example: magnesium and oxygenExample: magnesium and oxygen

cation anioncation anion-ide-ide Magnesium ox + ideMagnesium ox + ide magnesium oxidemagnesium oxide

Magnesium oxide is used as a drying agent.

Example 2: what is the name of CaExample 2: what is the name of Ca33NN22?? Ca = calciumCa = calcium N = nitrogenN = nitrogen Drop the end of the anion and add Drop the end of the anion and add -ide-ide Calcium nitrideCalcium nitride

Example 3:Example 3: What is the name of BaCl2? Barium chlorideBarium chloride

Writing Writing formulasformulas for Ionic for Ionic CompoundsCompounds

Remember: Remember:

positive charges must = negative chargespositive charges must = negative chargesExample: what is the formula for magnesium Example: what is the formula for magnesium

phosphide?phosphide?

Magnesium is MgMagnesium is Mg2+2+ phosphorous is Pphosphorous is P3–3–

Lowest common multiple of 2 and 3 is 6Lowest common multiple of 2 and 3 is 6 3 Mg3 Mg2+2+ ions and 2 P ions and 2 P3– 3– ions (6+ve charges and 6 –ions (6+ve charges and 6 –

ve) ve) MgMg33PP22

You try!You try!

What is the formula for calcium oxide?What is the formula for calcium oxide? calcium is Cacalcium is Ca2+2+ oxygen is Ooxygen is O2–2–

1 Ca1 Ca2+2+ ion and 1 O ion and 1 O2– 2– ionsions CaOCaO

Drawing Formula DiagramsDrawing Formula Diagrams

Examples on overhead:Examples on overhead:– Lithium nitrideLithium nitride– Barium sulphideBarium sulphide

WS – 4.2 Writing Ionic FormulasWS – 4.2 Writing Ionic Formulas p. 187 Practice Problems (#1 odd p. 187 Practice Problems (#1 odd

letters)letters) p. 188 Practice Problems (#2 even p. 188 Practice Problems (#2 even

lettersletters

Ionic Compound Ionic Compound with a Multivalent Metalwith a Multivalent Metal

Some transitional metals are Some transitional metals are multivalentmultivalent, meaning they have , meaning they have more than one possible charge).more than one possible charge).– On the periodic table, the On the periodic table, the most common most common

form form of the ion is listed on of the ion is listed on toptop– Roman numerals Roman numerals are used after the are used after the

metal name to indicate which ion was metal name to indicate which ion was usedused

Example:Example:

What is the formula manganese(III) What is the formula manganese(III) sulphide?sulphide?

This manganese is MnThis manganese is Mn3+3+ sulphur is Ssulphur is S2–2–

Lowest common multiple of 3 and 2 is 6Lowest common multiple of 3 and 2 is 6 2 Mn2 Mn3+3+ ions and 3 S ions and 3 S2– 2– ionsions MnMn22SS33

You try!You try!

What is the name for TiFWhat is the name for TiF44?? titanium can be Tititanium can be Ti4+ 4+ oror TiTi3+ 3+ fluorine is fluorine is

FF––

From the ratio in the formula you From the ratio in the formula you

can find out it is Tican find out it is Ti4+ 4+

1 Ti1 Ti4+4+ ion and 4 F ion and 4 F– – ionsions Titanium (IV) fluorideTitanium (IV) fluoride

Practice ProblemsPractice Problems

p. 190 (#1 odd letters)p. 190 (#1 odd letters) p. 191 (#1 even letters)p. 191 (#1 even letters)

Polyatomic IonsPolyatomic Ions

Polyatomic ions, are made up of several Polyatomic ions, are made up of several atoms joined together (ironically, joined atoms joined together (ironically, joined with covalent bonds)with covalent bonds)– The whole group has a + or – charge, not The whole group has a + or – charge, not

individual atoms.individual atoms. What is the formula of sodium sulphate?What is the formula of sodium sulphate?

Na+ and SO42–

Na2SO4

Example: What is the name of the compound Example: What is the name of the compound KClO?KClO?

K+ = potassium ClO– = hypochlorite Potassium hypochlorite

Example: What is the formula for Calcium nitrate?

Ca2+ and NO3-

Ca(NOCa(NO33))22

* Note the brackets around NO* Note the brackets around NO33 show there are two of the nitrate show there are two of the nitrate ions presentions present

Practice ProblemsPractice Problems

p. 193 (#1 and 2 odd letters)p. 193 (#1 and 2 odd letters) WS – 4.2 Ionic Naming WS – 4.2 Ionic Naming

– May have all three Ionic compoundsMay have all three Ionic compounds BasicBasic Multivalent metals (need roman numerals)Multivalent metals (need roman numerals) PolyatomicsPolyatomics

Naming Simple Covalent Naming Simple Covalent CompoundsCompounds

Prefixes are used before the atom name to indicate the number of atoms in the molecule.

Examples: CO = carbon monoxide, CO2 = carbon dioxide

Write the most metallic atom (furthest left) first, then add -ide to the end of the second atom’s name

Examples:Examples:

What is the name of the molecule What is the name of the molecule SiSi33PP66??

– TriTrisiliconsilicon hexahexaphosphidephosphide

What is the chemical formula for the What is the chemical formula for the molecule trinitrogen tetrachloride?molecule trinitrogen tetrachloride?– NN33ClCl44

Practice ProblemsPractice Problems

p. 195 (#1 and 2 even letters)p. 195 (#1 and 2 even letters) WS – 4.2 Covalent Naming WS – 4.2 Covalent Naming

AssignmentAssignment

How do you know which type it How do you know which type it is?is?

To determine whether a compound is To determine whether a compound is ionicionic or or covalentcovalent::

- Examine the formula- Examine the formula•Ionic compounds start with a Ionic compounds start with a metalmetal or the or the

ammonium ionammonium ion•Covalent compounds start with a Covalent compounds start with a non-non-metalmetal

Take the Section 4.2 Quiz

Comparing Ionic - CovalentComparing Ionic - Covalent

p. 197 (#1 and 2 all letters)p. 197 (#1 and 2 all letters) WS – 4.2 Mixed Chemical NamingWS – 4.2 Mixed Chemical Naming