protons - found in the nucleus of the atom; amount of charge =1.6X10^-19
atomic number (Z) - equal to the number of protons found in an atom of that element
neutrons - neutral molecules that don't have a charge
mass number (A) - the sum of the protons and neutrons in the atom's nucleus
isotopes - atoms that share an atomic number but different mass numbers
electrons - move through the space surrounding the nucleus and are associated with varying levels of
energy
valence electrons - farthest from the nucleus and have the strongest interac ons with the surrounding
environment and the weakest interac ons with the nucleus
ca on - posi vely charged atom
anion - nega vely charged atom
atomic mass - of an atom is nearly equal to its mass number
atomic weight - the number reported on the periodic table
ground state - state of lowest energy in which all electrons are in the lowest possible orbitals
, excited state - at least one electron has moved to a subtle of higher than normal energy
orbitals - regions of space around the nucleus
Periodic Table of Elements - shows that ordering the known elements according to atomic weight
revealed a pa ern of periodically recurring physical and chemical proper es
metals - found on the le side and in the middle of periodic table; include ac ve metals, transi on
metals, and the lanthanide and ac nide series of elements
non metals - found predominately on the upper right side of the periodic table; bri le; li le to know
metallic luster
metalloids - semimetals that share characteris cs with both metals and non metals
Ioniza on Energy - ioniza on poten al; energy required to remove an electron from a gaseous species
first ioniza on energy - the energy necessary to remove the first electron
second ioniza on energy - the energy necessary to remove the second electron
electron affinity - the energy dissipated by a gaseous species when it gains an elecrron
electronega vity - a measure of the a rac ve force that an atom will exert on an electron in a chemical
bond
Pauling electronnega vity scale - ranges from 0.7 to 4
alkali metals - possess most of the classic physical proper es of metals; densi es lower than those of
other metals; Group IA