C1.5History Of The Atom Flashcards
Who were the first people to come up with the idea that everything could be broken down into something(atom)?
Ancient greeks
What did john Dalton discover?
He discovered atoms were in spheres.
When did John Palton discover this?
1800
Who discovered in 1800 atoms were in spheres?
John dalton
What did JJ Thomson come up with
The plum pudding model
When did JJ Thompson create the Plum pudding model?
1897
Who created the plum pudding model?
JJ Thompson
When did Ernest Rutherford do his experiment
1909
What did Rutherford discover?
- Mass concentrated in the centre
- Most of the mass in the nucleus
- Most of the atom is empty space
- The nucleus is charged
- Plum pudding model disproven
Who proved the plum pudding model wrong?
Rutherford
What was the plum pudding?
A model that said negatively and positively charged atoms are everywhere in random places like fruit in a plum pudding.
Niels bohr date of discovery?
1913/1914 kerboodle and google say different things.
What did Bohr discover?
Electrons are in shells at set distances orbiting the nucleus.
Who discovered Electrons are in shells orbiting the nucleus?
Niels Bohr
When was James Chadwick’s discovery?
1932
What did James Chadwick discover?
Discovered neutrons
Who Discovered neutrons?
James Chadwick
What did Dalton suggest?
He suggested substances were made up of atoms like tiny hard spheres.
2: He also suggested that each chemical element had its own atoms that differed from others in their mass.
3: He also believed they could not be divided or split.
Who discovered the electron?
J.J Thomson
When was the electron discovered?
1897
What was discovered about the electron?
It has 1/2000 the mass of the lightest atom CHECK I AM NOT SURE.
How was the electron discovered?
Thomson’s experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons
Describe the experiment J.J Thomson did that discovered the electron.
Gas at very low pressure in a cylinder, a thin slit at the end glass glows through slit by rays coming from negative electrode(the streams of negative electrons.
What is the name pf the experiment that discovered the electron?
Cathode ray tube
Why did J.J Thompson come up with the plum pudding model?
He knew that atoms themselves were neutral so any charges must balance out. He imagined the electrons as bits of a plum pudding.
What is the name of the experiment carried our by Geiger and Marsden students?
The alpha particle scattering experiment.
What is Rutherford’s model of the atom called?
The nuclear model.
Describe the alpha scattering experiment.
Firing dense positively charged particles called alpha particles at the thinnest piece of gold foil they could make. They expected the particles to pass straight through the gold atoms with their defused cloud of positive charge(J.J Thompson theory). The positively charged particles must be in a tiny sport in the centre due to the large positive particles being fired being repelled back to the source. Therefore it was preposed electrons must orbit around the nucleus which contains dense and positively charged protons.
What did Niels Bohr notice?
The light given out when atoms were heated only had a specific amount of energy,he suggested electrons must be in shells and orbit at set distances because the energy given out must have been given out when exited electrons fall from a high to a low energy level (shell to shell) Bohr made a model for this.
How did scientists know there was something els something els in the atom before James Chadwick’s discovery?
There was missing mass that had been noticed in the atom. Scientists speculated there were two types of sub-atomic particles in the nucleus.
