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John Dalton used what 4 things to support his atomic theory...
- Greek Concept of the Atom
- Law of Definite Proportions
- Law of Conservation of Mass
- Law of Multiple Proportions
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The 5 Principles of Dalton's Atomic Theory are...
- All matter is composed of extremely small particles called atoms which cannot be subdivided, created, or destroyed
- Atoms of a given element are identical in their chemical and physical properties
- Atoms of different elements differ in their chemical and physical properties
- Atoms of different elements combine in simple, whole number ratios to form compounds
- In chemical reactions , atoms are combined, separated, or rearranged, but never created or destroyed
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Dalton's theory was able to explain most of the data collected from chemical reactions at that time but more current data shows that which two principles are no longer true?
The first two principles are not true because scientists can divide, create, and destroy atoms and atoms can combine with like atoms
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Daltons atom looks like
a simple sphere
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JJ Thomson is credited for the discovery of....
Electrons
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Where does the glowing beam originate from, according to Thomson?
from the atoms of the cathode because most of the atoms in the air had been pumped out of the tube
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What kind of charge does the glowing beam have inside the tube, according to Thomson?
negative
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How did Thomson confirm the charge of the glowing beam?
- When he placed a magnet by the tube he beam was deflected
- When a small paddle ray was placed in the path of the rays the wheel would turn
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Rutherford is knownfor what experiment?
The Gold Foil Experiment
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Describe Thomson's Atomic Model
Ball of positive charge with negatively charged electrons inside
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In the Gold Foil Experiment, Rutherford thought that the alpha particles would...
pass right through
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What acctually happened to the Alpha Particles?
some bounced back
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From the data that Rutherford collected, what did he propose about the structure of the atom?
Most parts of the Atom were empty space
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Rutherfords atom looks like...
a nucleus surrounded by empty space
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James Chadwick is credited for discoverign the...
Neutron
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Explain why scientists believed that there had to be another particle in the nucleus besides the proton
Mass of protons and electrons didn't equal the mass of the atom
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Rutherford equated the motion of electrons in the atoms to what
planets orbiting the sun
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Bohr described electrons as being in what?
Energy Levels
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What are the 7 points to Bohr's atomic theory
- Electrons are found in orbitals
- A set amount of electrons can be in the orbital at any given time
- Electrons act like particles that have mass
- All electrons are located in the the Electron Cloud
- Electrons can only be a certain distance from the nucleus
- Quantum of Energy: distance between two energy levels
- Electrons can only be in an energy level not between two
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__________ experiments showed that electrons behave like particles
Thomson's
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Evidence to support that electrons behave like particles
Although the mass of electrons is small electrons in a cathode ray still have enough mass to turn a paddle wheel
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________ experiments showed that electrons behave like waves
Louis de Brogile
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Evidence to support that electrons behave like waves
Said electrons could be conidered waves confined to the space around the nucleus
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The Quantum Model of the atom takes into consideration that electrons can act like both particles and waves. How does the Quantum Theory describe the location of the electrons in an atom
electrons within an energy level are located in orbitals
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