WGU C165 Unit 4: Chemistry

Matter

Anything that has mass and takes up space

Atom

Smallest particle of an element

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

A subatomic particle that has a negative charge

nucleus

Center of an atom

Electron Cloud

a region around the nucleus of an atom where electrons are likely to be found

Valence Electrons

electrons in the outermost shell

Element

pure substance that consists entirely of one type of atom

Atomic Number

the number of protons in an atom

Atomic Symbol

A one or two letter abbreviation for an element

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

Chemical Bonds

An attraction between two atoms resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells.

Molecules

Groups of two or more atoms held together by chemical bonds

Chemical

any substance that has a definite composition

organic compounds

carbon-based molecules

Pure Substance

A substance made of only one kind of matter and having definite properties.

Mixture

material composed of two or more elements or compounds that are physically mixed together but not chemically combined

Heterogeneous Mixture

A mixture in which different materials can be distinguished easily

Homogeneous Mixture

A mixture in which substances are evenly distributed throughout the mixture

Alloy

A mixture of two or more metals

Solid

A state of matter that has a definite shape and a definite volume

Liquid

A state of matter that has a definite volume but no definite shape.

Gas

A state of matter with no definite shape or volume

Physical change

a change of matter from one form to another without a change in chemical properties

Chemical Change

A change that occurs when one or more substances change into entirely new substances with different properties.

Chemical Reaction

the process by which one or more substances change to produce one or more different substances

Ion

An atom or group of atoms that has a positive or negative charge.

Ionic Bonds

Formed when one or more electrons are transferred from one atom to another

Covalent Bonds

Bonds created by sharing electrons with other atoms.

Metallic Bonds

a bond formed by the attraction between positively charged metal ions and the electrons around them

Periodic Table

A table that shows the elements, their atomic number, symbol, and average atomic mass; elements with similar chemical properties are grouped together.

Group

Vertical column in the periodic table

Period

A horizontal row of elements in the periodic table

metals

Elements that are good conductors of electric current and heat.

Nonmetals

Elements that are poor conductors of heat and electric current

Metalloids

Elements that have properties of both metals and nonmetals.

Conductive

malleable

any metal that can be rolled or pounded into flat sheets

Ductile

capable of being shaped or bent or drawn out

Law of Conservation of Matter

matter cannot be created or destroyed

Chemical Equations

A representation of a chemical reaction using symbols of the elements to indicate the amount of substance of each reactant and product.

balanced chemical equation

chemical equation with the same number of atoms of each element on both sides of the equation

Coefficients

The numbers in front of the chemical formulas thar indicates how many molecules take part in that reaction.

Subscripts

A number in a chemical formula that tells the number of atoms in a molecule or the ratio of elements in a compound

Reactant

A chemical substance that is present at the start of a chemical reaction

Product

A substance produced in a chemical reaction

Melting

The change in state from a solid to a liquid

Freezing

The change of state from a liquid to a solid

Condensation

The change of state from a gas to a liquid

Evaporation

The change of a substance from a liquid to a gas

Deposition

Process in which sediment is laid down in new locations.

Sublimation

A change directly from the solid to the gaseous state without becoming liquid