Bond Types & Covalent Bond Types & Covalent CompoundsCompounds

Mr. BimberMr. Bimber

Freedom High SchoolFreedom High School

Naming warm up:Naming warm up:

1.1. NaClNaCl

2.2. FeOFeO

3.3. CuCu22SOSO44

4.4. Tin (IV) CarbonateTin (IV) Carbonate

5.5. Ammonium bromideAmmonium bromide

1.1. Sodium chlorideSodium chloride

2.2. Iron (II) oxideIron (II) oxide

3.3. Copper (I) sulfateCopper (I) sulfate

4.4. Sn(COSn(CO33))22

5.5. NHNH44BrBr

Be happy! We’re MOOving on to reactions next!

Today you will learn:Today you will learn:

What every atom wants to be.What every atom wants to be. Three ways they can become what they Three ways they can become what they

want.want. How to name atoms that share electrons.How to name atoms that share electrons. How to write formulas for atoms that How to write formulas for atoms that

share.share. How to find what the bond is … really.How to find what the bond is … really. How bond type affects compound How bond type affects compound

properties.properties.

The “Big Picture”The “Big Picture”

Since elements are Since elements are the alphabet of the alphabet of chemistry, compounds chemistry, compounds are the words.are the words.

Different bonds make Different bonds make different compounds.different compounds.

We use different We use different naming rules for naming rules for different types of different types of compounds.compounds.

This is important because:This is important because:

We’re almost ready to start speaking We’re almost ready to start speaking sentences in chemistry. In other sentences in chemistry. In other words….words….

We’re almost ready to start making We’re almost ready to start making stuff happen.stuff happen.

What every atom wants…What every atom wants…

… … to have a full valence (outer) shell of to have a full valence (outer) shell of electrons.electrons.

The Noble Gas elements in family 18 The Noble Gas elements in family 18 already have a full valence shell. already have a full valence shell.

That’s why they don’t usually react That’s why they don’t usually react with other elements.with other elements.

Once other elements get a full outer Once other elements get a full outer shell, they usually become more stable shell, they usually become more stable and less reactive.and less reactive.

Three ways atoms get full shells:Three ways atoms get full shells:

When metals and nonmetals react:When metals and nonmetals react:1.1. Metals Metals lose outside electronslose outside electrons, so the , so the

full shell inside becomes the outside full shell inside becomes the outside shell. They become positive ions shell. They become positive ions (cations).(cations).

2.2. Nonmetals Nonmetals gain outside electronsgain outside electrons. . They become negative ions (anions).They become negative ions (anions).

3.3. Two nonmetals can Two nonmetals can share outside share outside electronselectrons. Neither element gets a . Neither element gets a charge.charge.

Covalent CompoundsCovalent Compounds

Two nonmetals sharing electrons Two nonmetals sharing electrons make covalent compounds. make covalent compounds.

There are many different There are many different combinations, so the name must say combinations, so the name must say how many of each element are in the how many of each element are in the compound.compound.

Covalent Names and Formulas:Covalent Names and Formulas:

Name the less electronegative element Name the less electronegative element first. (This is usually the element to the first. (This is usually the element to the left, and/or lower on the Periodic Table.)left, and/or lower on the Periodic Table.)

The second element gets an “-ide” ending.The second element gets an “-ide” ending. Use a prefix to say how many of each Use a prefix to say how many of each

element you have, but don’t use “mono-” element you have, but don’t use “mono-” on the first element.on the first element.

Examples: carbon dioxide, carbon Examples: carbon dioxide, carbon tetrachloride.tetrachloride.

Covalent Prefixes:Covalent Prefixes:• Mon(o) Mon(o) = 1= 1• Di Di = 2= 2• Tri Tri = 3= 3• Tetr(a) Tetr(a) = 4= 4• Pent(a) Pent(a) = 5= 5• Hex(a)Hex(a) = 6= 6

(Drop the ending “o” or “a” if (Drop the ending “o” or “a” if the element begins with a vowel.)the element begins with a vowel.)

Covalent Naming Practice:Covalent Naming Practice:

1.1. COCO

2.2. SOSO22

3.3. NN22SS33

4.4. Phosphorous Phosphorous

trichloridetrichloride

5.5. Dinitrogen pentoxideDinitrogen pentoxide

1.1. Carbon monoxideCarbon monoxide

2.2. Sulfur dioxideSulfur dioxide

3.3. Dinitrogen trisulfideDinitrogen trisulfide

4.4. PClPCl33

5.5. NN22OO55

Bonds affect compound properties:Bonds affect compound properties:

Ionic compounds usually form Ionic compounds usually form crystalline solids that have high crystalline solids that have high melting points and conduct melting points and conduct electricity. Most are soluble in water.electricity. Most are soluble in water.

Covalent compounds can be solid, Covalent compounds can be solid, liquid, or gas. They usually don’t liquid, or gas. They usually don’t conduct electricity.conduct electricity.

Bond type actually depends on Bond type actually depends on electronegativity difference.electronegativity difference.

– From 0 to 0.4, the bond is mostly covalent (electrons shared evenly).From 0 to 0.4, the bond is mostly covalent (electrons shared evenly).– From 0.4 to 1.0, the bond is slightly polar (uneven electron sharing).From 0.4 to 1.0, the bond is slightly polar (uneven electron sharing).– From 1.0 to 2.0, the bond is strongly polar.From 1.0 to 2.0, the bond is strongly polar.– Above 2.0, the bond is ionic (one atom takes electrons from the other.)Above 2.0, the bond is ionic (one atom takes electrons from the other.)

This is too complicated for naming purposes, so…This is too complicated for naming purposes, so… Just use the stair steps to choose which naming rules to Just use the stair steps to choose which naming rules to

follow.follow.

Traps and TipsTraps and Tips

First decide which First decide which

naming rules to use.naming rules to use.

Multiple charges?Multiple charges?

Polyatomic ions?Polyatomic ions?

Prefixes?Prefixes?

Only nonmetals make Only nonmetals make

covalent compounds.covalent compounds.

Naming is decided by Naming is decided by

the stair steps.the stair steps.

Electronegativity Electronegativity

difference is more difference is more

accurate.accurate.

SummarySummary

All atoms want a full valence shell.All atoms want a full valence shell. They do this by gaining, losing, or sharing They do this by gaining, losing, or sharing

their outside electrons.their outside electrons.– Metals lose, become cations.Metals lose, become cations.– Nonmetals gain from metals, become anions.Nonmetals gain from metals, become anions.– Nonmetals with nonmetals can share electrons.Nonmetals with nonmetals can share electrons.

Covalent and ionic compounds have Covalent and ionic compounds have different:different:– Naming rulesNaming rules– Compound properties.Compound properties.

Get it?Get it?

Name prefixes Name prefixes

one to six:one to six:

NN22OO44

ionic compound ionic compound

properties:properties:

Mono, di, triMono, di, tri

tetra, penta, hexatetra, penta, hexa

Dinitrogen tetroxideDinitrogen tetroxide

Water soluble solid,Water soluble solid,

high melting temperature, high melting temperature,

conduct electricityconduct electricity