Download Atomic Structure ppt File

BELL WORK
• What were the two most popular experiments that
helped develop the atomic model and theory?
• What is an isotope?
• What makes isotopes different?
STRUCTURE OF THE
ATOM
MR. SCHLAMB
THE NUCLEUS
• https://www.youtube.com/watch?v=FSyAehMdpyI
CATHODE RAY TUBES
• These cathode ray tubes led to the first discovery of
a subatomic particle the electron
• It was found that when the ray was exposed to a
negative electric field the ray would bend away
from the field
• This led to the conclusion that negatively charged
particles composed the ray and these became
named electrons
INFERENCES BASED ON ELECTRONS
1. Since atoms are electrically neutral they must
contain a positive charge to balance the
negative electrons
2. Because electrons have so much less mass than
atoms, atoms must contain other particles that
account for most of their mass
• With this knowledge the first model of the atoms
was purposed
PLUM PUDDING MODEL
RUTHERFORD GOLD FOIL EXPERIMENT
• This led to the discovery of the atomic nucleus
• https://www.youtube.com/watch?v=_uEFKG122dA
• Rutherford concluded that the center of an atom
which he called a nucleus contained positive
particles but was confused on where the electrons
were
NIELS BOHR
• One of Rutherford's associates purposed a new
model for the atom: Bohr’s model
OIL DROP EXPERIMENT
• https://www.youtube.com/watch?v=UFiPWv03f6g
NUCLEUS
• Usually like charges repel but in the nucleus 83
protons can exist and the nucleus still be stable
• The force that holds an atomic nucleus together is
referred to as nuclear forces
ISOTOPES
• Isotopes have the same number of protons but a
different number of neutrons
• This difference in neutrons changes the mass
number