Chemistry (Grade 9)

Matter, Properties, and Classification

Characteristics of matter

• Has mass and volume

• Cannot be created or destroyed,

• Can be classified, measured, and changed.

Particle Theory of Matter

• All matter is made of tiny particles with empty spaces,

• Particles attract each other; different substances have different particles

• Particles are in constant motion

• Particle motion increases with temperature.

Classifications of solid, liquid, and gas

• Solid - Rigid, fixed shape, fixed volume.

• Liquid - Not rigid, no fixed shape, fixed volume.

• Gas - Not rigid, no fixed shape, no fixed volume.

Composition of matter

Pure substances (elements and compounds) and mixtures (solutions and mechanical mixtures)

Physical properties of matter

Observed without destroying the substance (e.g., state, taste, odour, colour).

Chemical properties of matter

Indicates how a substance reacts with something else, resulting in a new substance.

Physical change

Change of form; easy to reverse; original substance still exists.

What is a chemical change?

Reactions; difficult to reverse; new substance formed.

Density

A physical property of matter calculated using mass and volume.

Element

Pure substance that cannot be broken down into simpler substances.

Compound

Pure substance composed of two or more elements chemically combined.

Periodic Table

Arrangement of chemical elements ordered by atomic number.

Alkali Metals (Group 1)

Shiny, silvery, soft and highly reactive.

Alkaline Earth Metals (Group 2)

Shiny, silvery, not as soft or as highly reactive

Halogens (Group 17)

Very reactive nonmetals.

Noble Gases (Group 18)

Very stable gases.

Subatomic particles

Proton (p+), Electron (e-), Neutron (n0)

Isotopes

Atoms of the same element with different numbers of neutrons.

Ionic compounds

Transfer of electrons, forming positive (cation) and negative (anion) ions.

Molecular compounds

Sharing of electrons (typically between two nonmetals).

Chemical formula

Tells the type and number of atoms in that compound.

Special elements

Hydrogen,Helium,Mercury and Bromine