Card Set Information
The histroy of the atom.
Also known as the cannonball model it decribes:
-All atoms are composed of individual atoms. (True)
-All atoms of a given elemnt are identical. (True)
-Atoms of different elemnts are different. (True)
-Compounds are formed by the combination of different elements. (True)
-Atoms are solid element with no sub-atomic particles. (False)
J.J. Thompon's Discovery
J.J. Thompson found out that:
-An atom contained negatively charged particles which are now known as electrons.
- He nick-named the design of the atom the "plum pudding model".
Ernest Rutherford's Experiment
Ernest Rutherford, a student of Thompson's, discovered:
-An atom, instead of having equal concentrations of protons and electrons had one central core with a positive charge.
- If the existance of the nucleus is true, then most of the atom is empty space.
-He figured this out in the
gold foil experiment
Neils Bohr figured out this from his studies:
-There was indeed a central nucleus with electrons orbiting around it.
-The space around the nucleus was made up of energy levels, each containing a specific number of electrons.
- This model was nicknamed the planetary of solar system model.
Schrodinger and deBroglie
Schrodinger and deBroglie came up up with the wave mechanical model stating:
-electrons are particles that move like a wave around the nucleus.
-electrons move in distinct energy levels called orbitals.
: a region of probablilty (heisenberg) or a place an electron is likely to be found.
In 1932 Chadwick discovered:
-by bombarding hydrogen with beryllium found that neutral gama rays were emmited.
-he named these particles neutrons.
Why did it take so long to discover neutrons?
-nuetrons have no chrage
-they have the same mass as a proton
-they reside in the nucleus with the proton
The Gold Foil Experiment
In the gold foil experiment Ernest Rutherford:
-positively charged particles were shot at a thin peice of gold foil using a Cathode Ray tube.
-if the plum pudding model was correct the particles would have passed through because they would hit a negative elctron and go through it.
-many of the particles were deflected and Rutherford tracked back and realized they all were deflected off something in the middle of the atom.
-this meant there was a dense structure with a positive charge in the middle of the atom
-found in the nucleus
-negative charge of one.
-found in orbitals around the nucleus.
-1/1836th of an amu.
-mass is neglible.
-positive charge of 1
-found in the nucleus
Unit of mass equal to one proton/neutron or 1.67x10
number of protons (identifies elemnt)
-number of protons plus number of neutrons (amu).
-you can get it by rounding the atomic mass to the neares integer.
number of protons equals number of electrons
Finding the number of subatomic particles.
Protons- equal to atomic number.
Electrons- equal to the amount of protons in a neutral atom.
Neutrons- The mass number-The atomic number
16- atomic number
16.00- atomic mass