Qualitative Chemistry

Valence Electrons

The electrons in an atom’s outermost orbit; determine the chemical

properties of an element.

Electron Dot Structure

Consist of the atomic symbol and dots which represent the number of electrons in the out most

energy level of than element

Octet Rule

States that atoms lose, gain, or share electrons in order to

acquire a full set of eight valence electrons.

Oxidation Number

The superscript which tells the charge of the element and the number of electrons it needs or can give up in order to be stable

Anion

A negatively charged ion

Cation

A positively charged ion

Monatomic Ion

An ion formed from only one atom

Polyatomic Ion

An ion made up of two or more atoms bonded together that acts as a single unit with

a net charge.

Coefficient

Is the number found in front of an ion or

compound. It tells the number of that ion or compound you have

Types of chemical bonds

• Ionic Bonds

• Covalent Bonds

• Metallic Bonds

Bonding Pair

Pair of valence electrons which bond two atoms together.

Lone Pair

Pair of valence electrons which are

not bonded to another element.

Unpaired Electron

A valence electron that is not partnered with

another electron.

Double Bond

Where two elements are bonded together

by two pairs of valence electrons. (4 electrons)

Triple Bond

Where two elements are bonded together

by three pairs of valence electrons. (6

electrons)

Physical ReactionWhen a substance

changes physically but the substance stays

the same.

Chemical ReactionWhen a substance

goes through a reaction and changes

into another substance.

Signs of Chemical Change• Change of color

• Release of gas

• Release of energy

• Release of heat

• Absorption of heat

• Release of light

Intensive Property

A physical property that remains the same no matter how much of a substance is present.

Extensive PropertyA physical property, such as mass, length, and volume, that is dependent upon the

amount of substance present.

Qualitative DataInformation describing color, odor, shape, or some other physical

characteristic.

Quantitative DataNumerical information describing how much,

how little, how big, how tall, how fast, etc.

MixtureWhen more than one compound is mixed together to form a substance. The

compounds can physically be separated.

Heterogeneous Mixture

One that does not have a uniform composition and in

which the individual substances remain distinct

Homogeneous Mixture

One that has a uniform composition

throughout and always has a single phase;

also called a solution.

Solute

A substance that is dissolved by another substance. There is

less of it.

Solvent

A substance that dissolves another

substance. There is more of it.

Unsaturated Solution

A solution that is able to dissolve additional

solute.

Saturated Solution

A solution that cannot dissolve any more solute

under the given conditions.

Supersaturated Solution

refers to a solution that contains more of the

dissolved material than could be dissolved by the

solvent under normal circumstances.

Phase Changes

• Solid

• Liquid

• Gas

• Plasma

Solid

The phase where the particles are held very

close together and hold a definite shape.

Liquid

The phase where the particles are held close together and do

not hold a definite shape. Usually takes the shape of the

container.

Gas

The phase where the particles are held near each other and has no

definite shape

Plasma

A state of matter where particles have been reduced to its most basic form. Usually found in stars

As a substance is heated, the particles move more, this causes the substance to expand. When cooled, the substance contracts. The exception to this is water, which expands when cooled and heated.

Ways Matter Change• Melting

• Freezing

• Evaporation

• Vaporization

• Condensation

• Sublimation

• Solid to liquid

• Liquid to solid

• Liquid to gas

• Liquid to gas

• Gas to liquid

• Solid to gas

Melting PointThe exact temperature

at which a solid changes into a liquid

Boiling Point

The exact temperature at which a liquid

changes into a gas

Heating Curve for Water

120 °C

steam 100 °C water steam

50°C liquid water

0 °C ice liquid -10 °C ice Heat added

Viscosity

A fluid’s resistance to flow

Accuracy and Precision

Precision

Is the degree of exactness to which the measurement of a quantity can be reproduced

Accuracy

Is the extent to which a measured value agrees with the standard value of a quantity.

Precision and Accuracy