Name:

Atomic Structure Classwork

Match the letter of the definition to the word in the lefthand column.

________ atom	a. Average of the masses of naturally occurring isotopes of an element, weighted by abundance.
________ nucleus	b. Neutral subatomic particle found in the nucleus.
________ protons	c. The space around the nucleus of the atom through which the electrons move.
________ neutrons	d. Central part of an atom made up of the protons and neutrons.
________ electrons	e. Mass of an atom in atom mass units it is the sum of the number of protons and neutrons.
________ electron cloud	f. Energy level of an electron that we model as the distance an e^- circles the nucleus.
________ electron shell	g. Negatively charged subatomic particle found in the electron cloud.
________ isotopes	h. Positively charged subatomic particle found in the nucleus.
________ atomic mass units	i. Number of protons in an atom.
________ atomic number	j. Tiniest particle of an element that has all the properties of the element.
________ mass number	k. Unit to describe the mass of atoms, molecules and subatomic particles.
________ atomic mass	l. Atoms of the same element having different numbers of neutrons.