Compounds and Bonds

Chapter 2 - Chemical Interaction

CompoundCompound

Chemical FormulaChemical Formula

SubscriptSubscript

Ionic BondIonic Bond

Covalent BondCovalent Bond

MetallicMetallic

Warm up: Define the following termson the front of your compounds packet

COMPOUND:

A substance made up of 2 or more different types of atoms bonded together

Chemical Formula:An expression that shows the number of and

type of atom in a compound

For example: C6H12O6Types of elements:

carbon, hydrogen and oxygenHow many (number):

6 Carbon, 12 Hydrogen, 6 Oxygen

Subscript:

A number written slightly below the and to the right of a chemical symbol that shows how

many atoms of an element are in a compound.

C6H12O6

Ionic bond:The electric attraction between a

negative and a positive ion.

Covalent Bond:

A pair of electrons shared by 2 atoms

Metallic Bond:

A certain type of bond in which nuclei float in a sea of electrons

Today's Topic:

How atoms are combined in a compound (bonded), determine the properties of the compounds

CHEMICAL BOND: The force holding 2 atoms together in a

compound.

3 Major Types of Bonds:

Metallic, Ionic, Covalent

Metallic Bonds: are caused by mobile (moving electrons), this gives metal atoms the freedom to move around,

therefore metal bend

Ionic Bonds: are caused by the formation of ions, this bond allows salt to dissolve in water.

When an ionic compound dissolves it separates into ions which conduct electricity.

Whereas covalent bonds do not!

Covalent bonds: the atoms share electrons, sometimes one atom pulls to hard on the

electrons giving the atom 2 oppositely charged ends.

What do you know about opposites:

THEY: __________________ATTRACT

Therefore these molecules will :stick to each other...this is called COHESION

COHESION: The attraction between

2 like Molecules!!!!

Example:

H2O

SURFACE TENSION ON A PENNY!

The water forms a bubble on the penny! This is due to

surface tension caused by the attraction of the water

molecules to each other. Instead of falling off the penny the water molecules hold each other in place creating a dome

on the penny.

Capillary Action:Take a look at your celery, write down

what you notice on the back of your lab.

Capillary Action - the tendency of water to

travel up a small narrow tube. This is also caused

by the polar covalent bonds in the water

molecule

COHESION: water to water, molecules of the same substance attract.

ADHESION: water to tube (xylem), molecules of different substances attract.

Water flow up the xylem of plant due to the uneq

Cohesion (attraction) between the water molecules, and the Adhesion between the

xylem and the water cause the water to move up the small tubes called xylem in the celery

MoleculeMolecule

Polar Covalent BondPolar Covalent Bond

NonPolar Covalent NonPolar Covalent BondBond

Warm up: Define the following termson the front of your compounds packet

MOLECULE

A group of atoms that are held together by covalent

bonds so that they move as a unit.

Polar Covalent BondThe unequal sharing of

electrons between 2 atoms that gives rise to negative

and positive regions of electric charge.

Non-Polar Covalent Bond

The unequal sharing of electrons between 2 atoms

COMPOUND:

A substance made up of 2 or more different types of atoms bonded together

CHEMICAL BOND: The force holding 2 atoms together in a

compound.

3 Major Types of Bonds:

Metallic, Ionic, Covalent

Compounds are 2 or more elements held together with a CHEMICAL BOND.

Properties of compounds depend on the elements that make them up and how those element are BONDED to each other. These properties are usually very DIFFERENT from the individual elements that make them up.

The same elements can form different different compounds with different properties:

Example:

H2O = water - safe to drink, does not kill bacteria

H2O2 = hydrogen peroxide, makes you

vomit, used to kill bacteria

-Bonding Occurs due to the fact that every atom wants to acquire:

8 VALENCE ELECTRONS

- VALENCE ELECTRONS: are the electrons in the outermost energy

level of an atom (farthest away from the nucleus)

- A Full valence shell requires 8 valence electrons. With the

exception of Helium because helium 1st energy level is filled with only 2.

Draw a Bohr model diagram of helium-4 and label the valence electrons

4

P:M:E:N:# valence e-:Questions: does helium-4 have a full valence shell: ____________

He

Draw a Bohr model diagram of carbon-14 and label the valence electrons

14

P:M:E:N:# valence e-:Questions: does carbon-14 have a full valence shell: ____________

C

Draw a Bohr model diagram of Neon-20 and label the valence electrons

20

P:M:E:N:# valence e-:Questions: does Neon-20 have a full valence shell: ____________

Ne

3 Main Types of Bond:

Metallic Bonds

Covalent Bonds

Ionic Bonds

1. METALLIC BOND: Bond between 2 METALS.

Considered to be a "sea of electrons" with positive and "islands" (nuclei)

Black = electrons, V=Valence electrons,

Blue = proton, Red = neutrons

2. COVALENT BOND: electrons are SHARED.

A bond between 2 NON-METALS

2 Types of Covalent Bond

POLAR and NON-POLAR

1. NON-POLAR BONDS: an equal sharing of electrons, between atoms. Occurs between 2 atoms of the same element.

v

v

2. Polar Bonds: an UNEQUAL sharing of electrons between atoms. Occurs between 2 atoms from different elements.

Bond between two different elements of atoms (element)

- Creating a slight negatively charges side and a slight positively charged side.

- The polarity causes CAPILLARY ACTION, ADHESION, COHESION, SURFACE TENSION, and allows plants move water up their stems for photosynthesis

CohesionAttraction between 2 LIKE molecules

(2 of the same types of molecules sticking together)

AdhesionAttraction between 2 UNLIKE molecules

(2 different type molecules sticking together)

Surface TensionCohesive forces in water that cause it to bead and form a thin elastic film layer

Capillary Action - the tendency of water to move up a narrow tube. (Caused by the adhesion (attraction) of the water molecule to the side of the tube, and cohesion (attraction) between the water molecules. The water sticks together and pulls a trail of water up the tube (attraction)).

3. IONIC BOND: Bond between 2 oppositely charged IONS.

A bond between a NON-METAL and a METAL

An electron is TRANSFERRED from the metal, creating a positive charged ion called the CATION. This transfer created a negatively

charged non-metal referred to as an ANION.

The POSITIVE ion is

attracted to the NEGATIVE ion, holding the two atoms together.

The positively charged ion can also be attracted to a positively charged particle referred to as a POLYATOMIC ion. Which is basically a compound (molecule) with a positive or negative charge.

EXAMPLE:NaCl: Table SaltMetal (cation) = __________, gives up

an electron creating a ______________ ion.

Nonmetal (anion) = _________, accepts the electron creating a

_____________ ion

Positive and negative charges _____________ each other, creating a bond holding the compound together.