What factor determines different elements?
Number of protons in the atom
What’s the format of notation of an element?
Atomic Number
Symbol
Atomic mass
What is atomic number
Number of protons
What’s the mass number?
Number of protons and neutrons
How do you determine the number of neutrons in a nucleus?
Mass number - atomic number
What path do alpha particles take?
Straight forward
Does altering the energy of an alpha particle affect the direction it takes?
No
How does increasing the number of particles affect the movement of them?
More deflections
How does adding neutrons affect the way alpha particles travel?
More neutrons repel alpha particles further
What did Rutherford experiment show?
The presence of a positive nucleus proves that atoms are mostly empty space
If neutrons were used in place of alpha particles…
There would be no repelling because neutrons have no charge
What particles contribute to mass number?
Protons and neutrons
What particles contribute to atomic number?
Protons
What particles contribute to net charge?
Protons and electrons
What is the name of John daltons theory?
Atomic theory
What did J.J. Thompson discover ?
Electrons
What charge do electrons have?
-
What are the Cathode rays made of in Thomson’s experiment?
Gas discharge tube
Why do electrons move to the positive end of the gas tubes?
They have negative charges, opposites attract
Describe thomson’s model
Observed cathode rays or movement of gas tubes, determining the movement came from negatively charged electrons moving to the positive end of the tube
What was Ernest Rutherford experiment called?
Gold foil experiment
What’s the charge of an alpha particle
Positive
Describe Ernest Rutherford experiment
He used a thin sheet of gold foil and shot alpha particles through it - some particles passed directly through the foil as if it wasn’t there. So, a positive nucleus repels positive particles and atoms are mostly empty space
