chapter 4: the structure of matter. section 1: compounds & molecules what are compounds? when...

Chapter 4: The Chapter 4: The Structure Structure of of MatterMatter

Section 1:Section 1:Compounds & MoleculesCompounds & MoleculesWhat are compounds?

When elements combine to form a compound, the compound has properties different from the elements that make it.◦NaCl

Chemical BondsChemical BondsChemical bonds distinguish

compounds from mixtures.◦Mixtures are made of

_________substances that are placed together. Each substance in the mixture keeps

its own properties.

Chemical Bonds are the attractive forces that hold different atoms together in a compound.

A compound always has the same chemical formula.◦Ex. Water _________◦Table Sugar C12 H22 O11

◦Glucose __________

A Chemical Formula shows the types & numbers of atoms in the compound

Compounds are always made of the same elements in the same proportions.

Chemical Structure shows the Chemical Structure shows the bonding within a compoundbonding within a compoundThe arrangement of atoms within a

compound determine many of its properties.◦Example: H2O

Bond Length: The avg. distance between the nuclei of 2 bonded atoms

Bond Angles: The angle formed by 2 bonds of the same atom.

Some structures are made of bonded ions.

Example: NaCl◦A repeating network connected by

strong bonds◦Positive Na bonded to Negative Cl

The strong attractions between oppositely charged ions give NaCl high melting & boiling points

Some compounds are made Some compounds are made of moleculesof molecules

Example: “Air”

Air contains Nitrogen, Oxygen, & Carbon Dioxide.◦All 3 substances are made of molecules

Atoms within each molecule are strongly bonded. The attraction between the different molecules are not as strong

Chapter 4 Section 2: Ionic & Covalent

Bonds1. The outermost energy levels of

a bonded atom is full of ____________.

2. Atoms bond when their __________ electrons interact.

3. Generally, atoms join to form bonds so each atom will have a full outer energy level.

Ionic Bonds4. Form between oppositely charged

ions4. Na+ Cl-

5. Metals form _______________ charged ions.

6. Nonmetals form____________ charged ions.

7. Ionic Bonds are formed by the ________of electrons.

Properties of Ionic Compounds1. Will form between metals &

nonmetals2. When melted or dissolved in

water, ionic compounds conduct ___________.

3. Electric current is moving charges

4. Solid ionic compounds do not conduct electricity because their particles have very little movement.

Metallic Bonds

1. Electrons move freely between metal atoms

2. A Metallic Bond is a bond formed by the attraction between positively charged metal ions & the elements around them

3. In metallic bonds the outer levels overlap and electrons move freely from atom to atom.

Covalent Bonds

1. Electrons are _________ between bonded atoms.

2. Often formed between nonmetals

3. Most covalent bonds have a ______ melting point

1. Due to weaker bonds between atoms.

4. Atoms are free to move in compound & do not conduct electricity (not charged)

Polar Covalent Bonds

When 2 different atoms share electrons, they are not shared ___________.

A Polar Covalent Bond is formed by the unequal sharing of electrons

Electrons are more attracted to the elements located on the far right (____________)

Polyatomic IonsCompounds that have both ________ &

___________ bonds are polyatomic

Example: Baking Soda & Ammonium nitrate

Parentheses group the atoms of a polyatomic ion. (NH4)2SO4

◦Indicate when elements act as a single ion.

The charge applies to the whole ion

Chapter 4 Section 3Chapter 4 Section 3Compound names & Compound names & formulasformulas

Compound names & formulas are related

Compound names reflect the elements which they are made of.

Group ChargesGroup 1 = 1+

Group 2 = 2+

Groups 3-12 (Tend to have more than one charge)◦ Can lose valence electrons as well as lower level electrons

Group 13 = 3+

Group 14 = 2+ or 4+

Group ChargesGroup 15 = 3-

Group 16 = 2-

Group 17 = 1-

Group 18 = 0 (stable/noble gases)

Lanthanides = 3+Actinides = 3+ or 4+

Naming Ionic CompoundsNaming Ionic CompoundsIonic Compounds are formed between anions & cations. (nonmetals & metals)

When atoms lose electrons they are written with a_________ charge ◦Ex. Sodium loses one e- (Na+)

Calcium loses two e- (Ca 2+)

Table 4-4 shows common names & symbols for cations.

An anion (________) that is made of one element has a name similar to the element

◦Example: Flourine becomes a flouride ion when combined with a cation.

◦Table 4-5 (common anions)

Most anions have the same charge as elements in their same _________.

Ex. Calcium ChlorideCalcium has a charge of ______Chlorine has a charge of ______

How can you balance the compound?

CaCl2

How can you determine the charge of a transition metal?

Like all compounds, ionic compounds have a total charge of ________.

This means the total positive charge of the cation must equal the total negative charge of the _________.

Example: An Oxide ion, O2- has a

charge of _____. 3 ions would have a total charge of ______.

Some cation names must show their chargeExample: FeO & Fe2O3

Iron is a transition metal which can form many cations each with a different charge. (table 4-6)

The cation must be followed by a Roman Numeral in parentheses◦Example Fe2O3 iron(III)oxide

Writing Formulas For Ionic Compounds

You can determine the formula for a chemical compound by looking at its name

Example: Aluminum Flouride

Practice Problems

1. Lithium Oxide

2. Beryllium Chloride

3. Titanium (III) nitride

4. Cobalt (III) Hydroxide

Practice Problems

1. Magnesium Bromide

3. Lithium Nitride

2. Rubidium Oxide

4. Potassium Sulfate

Ions will end in what suffix?Ions will end in what suffix?

What is the charge of a cation?

What is the charge of an anion?

Balanced Chemical compounds have an overall charge of what?

What is the charge of group one?

What is the charge of group 18?

What is the charge of group 2?

Naming Covalent CompoundsCovalent compounds are named

using different rules.

Numerical Prefixes are used to name covalent compounds of 2 elements◦Tell how many atoms of each element

are in the compound (Table 4-7)

Example: Triflouride Dinitrogen tetroxide

Numerical Prefixes (pg. Numerical Prefixes (pg. 126)126)

1 Mono-

2 Di-

3 Tri-

4 Tetra-

5 Penta-

6 Hexa-

7 Hepta-

8 Octa-

9 Nona-

10 Deca-

Practice Practice MnF3

FeO

Titanium(III) Sulfide

Practice Practice

1. Diarsenic Pentoxide

2. Carbon Dioxide

3. Tetraphosphorus Trisulfide

4. Phosphorus Hexoxide

Empirical FormulaA compound’s simplest formula is

its empirical formula.◦Tells the smallest whole-number

ratio of atoms in the compound

Example: H20 2:1

Scientists have to analyze unknown compounds to determine their empirical formula.

An unknown compound An unknown compound weighs 142 g.weighs 142 g.

It contains the O & P.It contains the O & P.

It has 62 g of P & 80 g of It has 62 g of P & 80 g of O. O.

How can you calculate its How can you calculate its empirical formula?empirical formula?

Convert the mass in to Convert the mass in to moles!moles!What is the conversion unit for

converting mass into moles?

How many moles of P have a mass of 62g?

How many moles of O have a mass of 80g?

Different compounds can have Different compounds can have the same empirical formula.the same empirical formula.

Example: Formaldehyde, Glucose, & Acetic Acid (Vinegar) all have the same empirical formula = CH2O

What formula can be used to determine the difference between similar compounds?

Its Molecular Formula!!

Molecular Formulas are determined from empirical formulas

Molecular formulas show the actual numbers of atoms in one molecule of a compound.

Covalent Compounds have both empirical & molecular formulas.

Chapter 4 Section 4Chapter 4 Section 4Organic & Biochemical Organic & Biochemical CompoundsCompoundsAn Organic Compound is a

covalently bonded compound made of molecules

In a covalent bond electrons are _________.

In an ionic bond electrons are __________.

Organic Compounds contain Organic Compounds contain __________.__________.

Almost always contain hydrogen

May contain oxygen, nitrogen, sulfur, & phosphorus

Carbon atoms form 4 covalent bonds in organic compounds

When a compound is made only of carbon & hydrogen it is a hydrocarbon◦Example: methane (C-H)

Carbon can also form double bonds or triple bonds with other atoms

Alkanes have Alkanes have singlesingle covalent covalent bonds & names end with bonds & names end with -ane-ane

Alkanes are hydrocarbons that have only single covalent bonds◦ Example: Methane C-H (simplest alkane)

Alkanes can also have bonds between carbons (C-C)◦ Example: Ethane C2H6

◦ Each Carbon atom bond with 4 other atoms

Arrangement of carbon atoms When 3 or more carbon atoms

are bonded they do not always line up in a row. (structurally)

When the atoms DO line up they are named “normal alkanes” ( n-alkane)

Alkanes with more than 3 carbon atoms have many possible arrangements.

They can be Branched, Unbranched, or form Rings (Figure 4-26)

Alkane formulas

Except for cyclic alkanes, the chemical formula always has a special pattern

The # for Hydrogen atoms is 2 more than twice the number of carbon atoms.

Example: C3 H8

Alkenes have Double carbon- carbon bonds (-ene)Alkenes are hydrocarbons

Different from alkanes because they have at least one double covalent bond between carbon atoms

C=C

Alkenes

Examples:

Ethylene C2H4

Propylene C3H6

Alcohols have –OH groupsend in “ -ol ”Alcohols organic compounds are

made of Oxygen as well as hydrogen & carbon

Alcohols have hydroxyl, or –OH groups

Example: Ethanol◦CH3CH2OH

Alcohol molecules behave similarly to water molecules

Neighboring molecules are attracted to one another◦Properties of adhesion & cohesion

Alcohols are liquid at room temperature but have very high boiling points

PolymersLarge molecules made of smaller

subunits

Many polymers have repeating subunits◦Example: polyethene

Polymers exist naturally & can be synthetic

Natural: rubber, wood, cotton, wool, starch, protein, DNA

Synthetic: Plastics or Fibers

A Polymer’s elasticity is determined by its structure

(Similar to a chain) When the monomers are liked together the polymer becomes elastic.

Biochemical Compounds

Naturally occurring organic compounds that are very important to living things.

Example: Carbohydrates, Proteins, & DNA

1. H7Cl2 _________________________________

2. C4Br6 __________________________________

3. P3O10 _________________________________

5.N5F8

________________________________

Naming Ionic Practice:

__________________________ CaCl2

________________________ K2O

___________________________ MgO

Chapter 4 Vocabulary Quiz

1. A compound 1. A compound made only of made only of hydrogen and hydrogen and carboncarbon

2. The simplest chemical formula of a compound that tells the smallest whole number ratio of atoms in the compound

3. Any one of 20 different naturally occurring organic molecules that combine to form proteins

4. Any organic 4. Any organic compound that is compound that is made of carbon, made of carbon, hydrogen, & oxygen hydrogen, & oxygen and that provides and that provides nutrients to the cells nutrients to the cells of living thingsof living things

5. Any covalently bonded compound that contains carbon

6. A biological polymer made of bonded amino acids

7. A large organic 7. A large organic molecule made of molecule made of many smaller many smaller bonded unitsbonded units

8. Hydrocarbons 8. Hydrocarbons that have only that have only singlesingle covalent covalent bondsbonds

9. A Chemical Formula that reports the actual numbers of atoms in one molecule of a compound

10. A bond formed by 10. A bond formed by the attraction between the attraction between oppositely charged oppositely charged ionsions