History Of The Atom Flashcards
Ernest Rutherford
The Nuclear Model
John Dalton
The Billiard Ball Model
Schrodinger
The Wave Mechanical Model
JJ Thompson
The Plum Pudding Model / The Currant Bun Model
Neils Bohr
The Planetary Model
Difference: JJ Thompson & Ernest Rutherford (2)
Thompson - Positive sphere with negatives imbedded
- Mass is due to the electrons
Rutherford - Negative sphere with positives imbedded
- Mass is due to the nucleus (99,9%)
The Billiard Ball Model Discoveries: (4)
- Matter consists of tiny particles called atoms. Can’t be broken up.
- Element have the same kind of atoms, mass and behavior.
- Atoms combine to form compounds in a fixed ratio
- A chemical reaction takes place when there is a rearrangement of the atoms.
Difference = Ernest Rutherford & Neil’s Bohr (1)
Rutherford - Said nothing about the movements of the electrons.
Bohr - Said electrons orbited around in energy levels depending on the amount of energy it contained.
The Plum Pudding Model = Discoveries (3)
- Negative sphere with positives imbedded in it.
- The atom was electrically neutral
- The mass of the atom was due to the electrons
Neil’s Bohr & Schrodinger = Difference (1)
Bohr - Electrons orbit in fixed paths around the nucleus depending on their amount of energy.
Schrodinger - Electrons travelled in orbitals and looked like clouds.
The Nuclear Model = Discoveries (4)
- Negative sphere with positives imbedded.
- 99,9% of mass is due to the nucleus.
- Nucleus is positively charged.
- The rest of the volume is due to the circling electrons.
In Rutherfords experiment with the gold foil. State the observations and interpretations. (3x3)
O - Most alpha particles moved through undefeated.
I - An atom is made up of mainly empty space.
O - Some particles were deflected by a small angle.
I - The nucleus was tiny and had to be positively charged, so was the alpha particle.
O - Occasionally, the alpha particles travelled back from the foil.
I - The nucleus carries most of the atoms mass.
Explain Rutherfords Expiriment: (3)
He beamed alpha particles at a piece of thin gold foil and detected the scintillations on a screen.
What is an Alpha particle? (4)
- It has protons and neutrons. (He nuclei = 2 protons, 2 neutrons) - It is very heavy - It is positively charged - Unstable
What is a Beta particle? (3)
- Light
- Negatively charged
- Electron
Ernest Rutherford
What is Radioactivity? (1)
- The giving off of particles.
Heavy nuclei= (2)
- Unstable
- Decays (spontaneous split. Emits stray particles)
= Radioactive
How thick was the gold foil in Rutherford’s experiment? (1)
0,00004cm thick
A few 100 atoms thick
JJ Thompson beamed what kind of rays and what charge were they? (1+2)
- Cathode Rays
- Negatively Charged
- Electrically Charged
Explain Thompson’s Expirement? (5)
- Parallel metal plates connected to a battery
- In glass Tube
- Filled with glass
- As gas pressure decreased = gas began to glow
- Placing magnets above and below tube = DEFLECTION happened.
Who created the neutron and 3 properties? (1+3)
= James Chadwick
- Same mass as proton
- Neutral
- Found in the nucleus
What is an energy level? (1)
Region of space where an electron has fixed energy.
Neil’s Bohr Time
What was the law of physics? (2)
- Electrons give off light
- Collapsing atom as a result
Frequency (1)
- Number of vibrations per second.
Why is blue light faster than red? (2)
- Vibrates faster
- Therefore more energy
How to colour travel in Air and Solid Transparents? (2)
Give 2 examples of Solid Transparents (2)
- Air = same speed
- Solid Transparents = Different speeds
- Glass and Water
Why does red light travel faster than blue in glass? (2)
- Glass causes blue light to bend more when it travels through a
- Denser medium
White light through a prism creates? (1)
- A continuous spectrum (all 7 colors)
Line spectrum is when what happens? (3)
- Electrons are in an excited state
- Release energy (quantum jump)
- To return to ground state
- This gives off light
= The line spectrum
Quantum Energy? (1)
- Difference in energy from one energy level to another
What is the formula for the max. number of electrons? (2)
- 2n^2
What is Ground state, Quantum jump and Excited state? (3)
- electrons at lowest energy state
- Jumping from one energy level to another
- When electron gains energy
Electromagnetic spectrum? (1)
- The Balmer Series
Ultra-Violet Spectrum? (1)
- The Lyman Series
What is so fascinating about line spectrums? (1)
- Every element has a different atomic emission spectrum.
- Like a fingerprint
Schrodinger replaced Bohrs energy level orbits with? (1)
- “clouds” “orbitals”
Probability of the orbitals is shown as what and where does it go? (2)
- Lobes
- Extends from the nucleus in 3 dimensions
What is an orbital? (2)
- An orbital is a three dimensional region around the nucleus where there is a high probability of finding an electron with a certain amount of energy.
