CHEM 1201 Chapter : Chapter 2
Document Summary
Atomic theory of matter: the theory that atoms are the fundamental building blocks of matter reemerged in the early 19th century, championed by john. Subatomic particles: protons and elections are the only particles that have a charge, protons and neutrons- essentially the same mass, the mass of an electron is so small we sometimes ignore it. Number of electrons = number of protons = atomic number. Number of neutrons = mass number atomic number. Mass number = numbers of protons + numbers of neutrons. Isotopes: atoms of the same element with different masses, different numbers of neutrons, all atoms with the same symbol have the same proton count. Noble gases (or rare gases) he, ne, ar, kr, xe, rn. *also learn the first row of transition metals. Periodic table summary: columns in the periodic table are called groups, rows in the periodic table are called periods.
