pt 1: NYS Chemistry Regents Essential VOCAB

Atomic Structure & Periodicity

Atom

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

Atomic mass

the weighted average mass of all isotopes of an element

Atomic number

the number of protons in an atom’s nucleus; determines the element’s identity

Electron configuration

the arrangement of electrons in an atom’s orbitals

Ion

an atom or group of atoms with a net electric charge due to loss or gain of electrons

Isotope

atoms of the same element with different number of neutrons

Nucleus

the dense center of an atom containing protons and neutrons

Orbital

a region of space where there is a high probability of finding an electron

Period Trend

predictable patterns in properties of elements across the periodic table

Valence Electrons

electrons in the outermost shell of an atom that participate in bonding