Mid-Year Review

Chemistry, Earth History, Infectious Diseases, Lithosphere

Chemistry 8.P.1- Understand the properties of matter and changes that occur when matter interacts in an open and closed container.

Physical and Chemical Properties

Physical Property- A characteristic that you can observe without changing the composition of the substance. Ex.- odor, mass, density, state, volume, color.

Chemical Property- A characteristic that you can only observe by changing the identity of the substance. Ex.- flammability, re-activity

Physical and Chemical Change

Physical Change- Any change that does not involve a change in the substance's chemical identity.

Chemical Change- Any change in matter that results in the formation of new chemical substance.

Elements, Compounds, and Mixtures

Elements- Building blocks of matter made of atoms.

Compounds- Substance formed when 2 or more elements chemically combine.

Mixtures- Combination of 2 or more different substances that are mixed but not combined.

Periodic Table

Periodic Table- A list of all known elements, increasing by atomic number.

Groups- Columns (up and down) of elements on the periodic table that share common properties.

Periods- The periodic table has seven horizontal (left to right) rows

Metals- Solid, shiny, good conductors of electricity and heat, and can be made into wires.

Non-Metals- Brittle, not good conductors of both heat and electricity, and can gain electrons in chemical reactions. Some nonmetals are liquid.

Metalloids- Have properties that are somewhat of a cross between metals and non metals, because of their unique conductivity properties, they can be used as a semiconductor or in computer chip.

Atomic Number- The number of protons in the atoms nucleus

Atomic Mass- The mass of an atom

Protons- A particle of a positive electric charge in an atom

Electrons- A particle of a negative electric charge in an atom

Neutron- Same mass as a proton but without the electric charge

Law of Conservation of Mass

Law of .....- States that matter cannot be created or destroyed ; it can only be transferred from state to state.