Unit 10- Chemical Bonds

Atom Inventory

How many atoms of each element the compound has

Octet Rule

Atoms combine to become more chemically stable when they obtain 8 electrons in their outer shell.

Valence Electrons

Electrons in the outermost shell

Lewis Structure

Write element symbol in the middle, follow with dots going clockwise based on the amount of valence electrons.

Chemical Bonding

A force that holds the atoms together in a substance. When atoms lose, gain, or share electrons they become stable and form chemical bonds.

Ions

Atoms that have a charge. They form by losing of gaining electrons.

Cations

Have a positive charge. They form by losing electrons.

ex. Magnesium- Mg+2

Anions

Have a negative charge from gaining electrons.

ex. Oxygen- O-2

Ionic Bond

When atoms of opposite charges combine

(electrons are transferred)

ex. MgCl2

Covalent Bond

When atoms share electrons

ex. Cl2

Polar Molecules

Have a positive and negative end because of unequal sharing of electrons.

ex. Water, H2O

Non- Polar Molecules

Does not have oppositely charge ends

ex. methane, CH4

Ionic Bonding

metal and non-metal

cation and anion

transfer of electrons

solids at room temp.

Covalent

2 or more nonmetals

2 or more anions

share electrons

gases at room temp.

Monatomic

Single atom with charge (Na+)

\*all of these will be on the periodic table

Polyatomic

Group of covalently bonded atoms that act as a group and carry an overall charge (NH4+)

\*most of these will be on the back of the periodic table

2

How many words will always be in the name of the formula

No

Do you use prefixes when naming ionic compounds?

Chemical Reaction

One or more substances is changed into different substances (chemical change)

Reactants

starting materials (present before a reaction)

Products

ending materials (present after a reaction)

Law of Conservation of Mass

Total mass of reactants must equal total mass of products

Signs of a Chemical Reaction

Bubbles

Heat energy/ light absorbed or released

Color change

Odor change

Formation of a precipitate (solid)

Yield

What does this sign mean?

Reversible Reaction

What does this sign mean?

Solid

(s)

Liquid

(l)

Gas

(g)

Aqueous

(aq)

(dissolvable in water)

Heat is Applied

What does this sign mean?

Catalyst is added to speed up reaction

What does this sign mean?

Balanced Equation

An equation that has the same number of atoms of each element on both side of the yield sign.