Periodic Table & Atoms Vocabulary

atomic number

• Number of protons in the nucleus

• Number of neutrons in the nucleus

• Total number of electrons in an atom

• Mass number of the atom

atomic mass

• The sum of the protons and neutrons in an atom

• The total number of electrons in an atom

• The average mass of all isotopes of an element

• The mass of an atom's nucleus only

metalloid

• has properties of both metals & nonmetals and appears along the stair step line of the periodic table

• is a pure metal that conducts electricity well

• is a nonmetal that is brittle and does not conduct electricity

• is a synthetic element that does not occur naturally

group/family

• the rows going left to right on the periodic table; elements in a row share properties and have the same number of valence electrons

• the columns going up and down on the periodic table; elements in column share properties and have same number of valence electrons

• the sections of the periodic table that contain metals only

• the areas of the periodic table that represent different states of matter

electron cloud (Quantum Mechanics)

• Electrons follow fixed orbits around the nucleus.

• Electrons tend to occur more frequently in energy levels around the nucleus at any given time.

• Electrons are stationary and do not move around the nucleus.

• Electrons are found only in the nucleus of an atom.

compound

• A substance made of two or more elements that are chemically combined

• A mixture of different substances that can be separated

• A single element in its pure form

• A solution where one substance is dissolved in another

period

• the rows going left and right on the periodic table; elements in row have same number of energy levels

• the columns going up and down on the periodic table; elements in column have similar properties

• a measure of the time it takes for one complete cycle of a wave

• a type of chemical bond between two atoms

atom

• The smallest unit of a chemical element, consisting of protons, neutrons, and electrons.

• A type of molecule that contains two or more atoms bonded together.

• A particle that is smaller than an atom and does not have a defined structure.

• A form of energy that is released during chemical reactions.

proton

• Subatomic particle in an atom that is positively charged and is in the nucleus of an atom

• Negatively charged particle found outside the nucleus

• Neutral particle found in the nucleus of an atom

• A type of molecule that forms chemical bonds

element

• A substance made of two or more different atoms

• A substance in which all the atoms in a sample are alike

• A mixture of various compounds

• A solid that can conduct electricity