Chapter 5: Atomic Structure and the Periodic Table

electron

a negatively charged subatomic particle

proton

a positively charged subatomic particle found in the nucleus of an atom

neutron

a subatomic particle with no charge and a mass of 1 amu (atomic mass unit); found in the nucleus of the atom

periodic table

an arrangement of elements into rows and columns according to similarities in their properties

isotope

atoms of the same element that have the same atomic number but different atomic masses due tot a different number of neutrons

nucleus

the dense central portion of an atom, composed of protons and neutrons

mass number

the goal number of protons and neutrons in the nucleus of an atom

atomic number

the number of protons in the nucleus of an atom of an element

atom

the smallest particle of an element that retains the properties of that element

atomic mass

the weighted average of the masses of the isotopes of an element