Chemistry: Final Terms

Anion

Atoms made up of MORE ELECTRONS (-) than protons (+), giving them a NEGATIVE charge

Atom

Originally thought to be the smallest form of matter, but made up of a number of smaller particles (protons, neutrons, and electrons). They also have the same number of protons to electrons.

Atomic mass number

the total number of protons (+) and neutrons in an atom.

Cation

Atoms made up of MORE PROTONS (+) than electrons (-), giving them a POSITIVE charge.

Chemistry

the study of the composition, structure, and properties of substances and...the transformations that they undergo.

Compound

Two or more elements combined chemically and specific proportions of each element. Ex. table salt = the elements sodium and chlorine.

Electron

smaller than protons, they carry a NEGATIVE charge and orbit around the nucleus.

Element

A substance that is made up of only one type of atom.

Gas

A form of matter that has no definite shape, weight or size. They are often invisible.

Ion

Atoms that DO NOT have the same number of protons to electrons.

Liquid

A form of matter that doesn't have definite shape, but has a definite weight and size. Ex. drink in a 12 oz. can, 2-liter, glass, etc.

Matter

Everything we see around us, from dirt and water, to air or a spoonful of salt.

Mixture

Two or more elements that are combined physically and the amount of each element in it can vary.

Neutron

One of the principal particles in an atom. it has NO electric charge (neutral) and is found in the nucleus along with protons.

Plasma

a mysterious substance that exists in conditions of extreme heat i.e. on the sun (or stars).

Proton

One of the principal particles of an atom. It has a POSITIVE electric charge, and is found in the nucleus of an atom.

Solid

A form of matter that has a definite shape, size, and weight. Ex. pencil

(4) Forms of Matter

Solids, liquids, gases, and plasmas.

Nucleus

center of the atom

electron configuration

The organization of electrons around the nucleus of an atom.

valence electrons

Electrons in the outermost (usually incomplete) shell.

kernel

The nucleus (protons & neutrons) and the electrons that are in the full (interior) shells of an atom.

Atomic Weight

the number of protons plus the number of neutrons

Covalent bond

a chemical bond that involves sharing a pair of electrons between atoms in a molecule

Electron cloud

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

Energy level

A REGION surrounding the nucleus of an atom, also called a shell. Electrons move around the nucleus in these.

Ionic bond

A chemical bond between two elements. It occurs when one atom gives electrons to the other atom, making both atoms into tons that bond with each other.

Molecule

two or more atoms held together by covalent bonds

Molecular weight

A measurement describing the heaviness of a particular combination of atoms.

Nucleus

The central core of an atom. Made up of protons and neutrons.

Periodic Table of Elements

A system of organization for the elements. Elements are placed based on their atomic number and type.

Shell

An ORBIT surrounding the nucleus of an atom.

Atomic Number

The number of protons contained in an atom. Used to identify elements.

metal

In the Periodic Table, the MOST ABUNDANT of the (3) broad categories by which elements are classified. These elements are good conductors of electricity and have a metallic sheen. They can be molded or stretched without breaking.

metalloid

In the Periodic Table, one of the (3) broad categories by which elements are classified. These are also called semimetals or semiconductors.

nonmetal

In the Periodic Table, one of the (3) broad categories by which elements are classified. In solid form, these do not gleam, are poor conductors, and tend to be fragile.

period

The name for a row in the Periodic Table. The lower this is, the higher the energy level (shell)