1. Ch. 11 Section 1 Review Development of the Atomic Theory

2. Vocabulary To Know  Atom- the smallest unit of an element that maintains the properties of that element  Electron- a subatomic particle that has a negative charge  Nucleus- an atom’s central region, which is made up of protons and neutrons  Electron cloud- a region around the nucleus of an atom where electrons are likely to be found

3. Beginning of the Atomic Theory  Matter is made of particles, which we call atoms.  An atom is the smallest particle into which a element can be divided and still be the same substance.  Electrons are located throughout the atom within the electron cloud.  The nucleus is the center part of an atom.