Democritus-named the atom
atom is the smallest particle into which an element can be divided and still be the same substance!
Atoms are seen with an electron microscope.
Dalton’s Atomic Theory
All substances are made of atoms. Atoms are small particles that connot be created, divided, or destroyed.
Atoms of the same element are exactly alike, and atoms of different elements are different.
Atoms join with other atoms to make new substances.
Thomson discovered electrons
Electrons-A subatomic (smaller than an atom) particle that has a negative charge.
Rutherford discovered the nucleus.
Nucleus-An atom’s central region, which is made up of protons and neutrons.
Bohr discovered electrons move around the nucleus in certain paths, or energy levels.
Schrodinger and Heisenberg found that the exact path of an electron cannot be predicted.
Electron Cloud-A region around the nucleus of an atom where electrons are likely to be found.