4.1 COMPOUNDS AND MOLECULES

ELEMENTS – a review…

• Made of individual atoms.

• Cannot be broken down into simpler substances.

• Listed on the periodic table.

• Created to be the building blocks of all matter.

MIXTURES – a review…

– Different substances just placed together.

– Substances keep their individual properties.

– Easily separated like sand and gravel.

COMPOUNDS

• Two or more elements bonded together = COMPOUND.

• Have properties different from the original element.– Have a chemical formula– Not easily separated.– New properties!!!!

• Atoms are to elements as molecules are to compounds!!

MODELS OF COMPOUNDS

A. BALL AND STICKB. SPACE FILLINGC. STRUCTURAL FORMULA

STRUCTURE AND PROPERTIES

A. Network structure - ATOMSSiO2 (strong, rigid, high melting point)

EXAMPLE:B. Network structure - IONS

NaCl (strong, rigid, high melting point)EXAMPLE:

C. Molecule groups C12H22O11 (weak bonds, low melting point)

EXAMPLE:

4.2 IONIC, METALLIC, AND COVALENT BONDING

How could you get pieces of paper to bond (stick together)?

Atoms BOND (stick together) when their outer energy level (VALENCE) electrons interact.There will be THREE different kinds of bonding.

1. IONIC BONDS• Electrons are transferred from one atom to

another creating ions.• Then the bond is formed between oppositely

charged ions.• Ionic compounds are in the form of a network

of particles.• Ionic compounds conduct electricity when

melted or dissolved in water.

2. METALLIC BONDS• Electrons are free to move from atom to

atom.

• Atoms are tightly packed together.

• Metals are: flexible, can bend and stretch, and can conduct electricity.

3. COVALENT BONDS

• Formed when atoms share electrons.

• Often form from nonmetals.

• Most have low melting points.

• Do not conduct electricity well.

BONDING SUMMARY(how to tell what type of bond is

holding a molecule together) Periodic Table

METAL + NONMETAL =IONICNONMETAL + NONMETAL = COVALENT METAL+ METAL = METALIC

METALNONMETAL

POLAR AND NONPOLAR COVALENT BONDS

POLAR

DIFFERENT TYPES OF ATOMS DO NOT SHARE ELECTRONS EQUALLY

NONPOLARATOMS OF THE

SAME TYPE SHARE THE ELECTRONS EQUALLY

WORKING WITH MODELS 4.2B

H2 COVALENT H-H

H20 COVALENT H-O-H

NaCl IONIC Na-Cl

Cl2 COVALENT Cl-Cl

O2DOUBLE COVALENT O=O

N2TRIPLE COVALENT N N

CO2 COVALENT O=C=O

C2H2 COVALENT H-C C-H

4.3COMPOUND NAMES AND

FORMULAS

Figuring out how to do assignment #1…Where do I start???

TYPES OF IONS

CAtION – ION WITH A POSITIVE (+) CHARGE

ANION – ION WITH A NEGATIVE (-) CHARGE

PERIODIC TABLE

METALS NONMETALS

+1

+2

-2

-1

NOBLE

GA S

CATIONS ANIONS

TRANSITION METALS

+1 OR +2

POLYATOMIC IONS

NAMING IONIC COMPOUNDS

(Na+) NaCl (Cl-)

Sodium Chloride

(Mg2+) Mg + F (F-)

MgF2

Magnesium Flouride

NAMING COVALENT COMPOUNDS

ELEMENTS GET A NUMERICAL PREFIX THAT INDICATES HOW MANY ATOMS ARE PRESENT – (table 4-7)

ELEMENTS TO THE RIGHT ARE NAMED SECOND AND END IN “IDE”

4.4 ORGANIC COMPOUNDSWhat does it mean to be

organic?This is the common

definition…

In Chemistry, an ORGANIC COMPOUND…

• Contains the element CARBON and ALMOST always HYDROGEN.

• CARBON is a SPECIAL ATOM: BECAUSE IT CAN BOND WITH FOUR OTHER ATOMS. (valence 4)

HYDROCARBONS

• Contain ONLY HYDROGEN and CARBON

ALKANE – a special hydrocarbon

• Hydrocarbons with SINGLE COVALENT BONDS

• The simplest one is: CH4 = METHANE (table 4-9)

• Others may form CHAINS, BRANCHES, or RINGS of hydrogen and carbon.

ALKENE – another type of hydrocarbon

• A hydrocarbon with DOUBLE COVALENT BONDS

C2H4 = ETHYLENE

ALCOHOL – another organic molecule

• Alcohols contain the: (OH) atom group

• CH3OH = METHANOL

• The rest just add (OH) to the appropriate alkane in table 4-9….

POLYMERS• SMALL ORGANIC MOLECULES THAT BOND

TO FORM LONG CHAINS OF MOLECULES:

C2H4….= POLYETHYLENE

• Some polymers are NATURAL CREATIONS of God: WOOD, STARCH, PROTEIN.

• Some polymers are MAN-MADE: PLASTICS

CHAPTER FOUR TESTSTUDY THIS:

• MIXTURE or COMPOUND

• NETWORK structure or MOLECULE group

• IONIC bond or COVALENT bond

• Will a substance conduct electricity? Explain.

• Chapter vocabulary words

• ION location on the Periodic Table (notes)