Module 8 Atomic models Flashcards
What was Max Planck’s contribution to the atomic model?
Planck introduced the concept of quantized energy in 1900, marking a significant departure from classical physics.
What was ** Heisenberg**’s contribution to the atomic model?
Heisenberg’s in 1925 introduced the uncertainty principle, stating you can’t find both the speed and the position of the electron. If you measure one you can’t find the other.
What was ** Schrödinger**’s contribution to the atomic model?
Schrödinger developed wave mechanics and his eponymous equation in 1926, describing the quantum state evolution of a physical system.
Who proposed the Plum Pudding Model and how did it characterise atoms?
J.J. Thomson proposed the Plum Pudding Model, depicting atoms as positively charged spheres with embedded electrons.
What experimental evidence supported the Plum Pudding Model?
Observations from cathode ray experiments and electrical conductivity studies provided support for the Plum Pudding Model.
who discovered the first atomic model?
The first people who discovered the first atomic model was Leucippus and Democritus.
What pivotal experiment laid the foundation for the Plum Pudding Model?
Thomson’s cathode ray experiment revealed the existence of electrons, contributing to the development of the Plum Pudding Model.
What subatomic particles did the Plum Pudding Model acknowledge, and how did it differ from earlier models?
The model acknowledged the presence of electrons within atoms, departing from earlier indivisible atom models.
What significant challenge did the Plum Pudding Model face, particularly from the Geiger-Marsden experiments?
The model struggled to explain the scattering of alpha particles observed in the Geiger-Marsden experiments, highlighting its limitations.
What experiment did Ernest Rutherford conduct to develop his nuclear model of the atom?
Ernest Rutherford conducted an experiment where he fired a beam of positively-charged alpha particles at gold foil.
What were the observations made by Rutherford during his experiment?
During his experiment, Rutherford observed that although some alpha particles bounced back, most of them went through the gold foil.
What did the first atom look like?
It was a round sphere. Like this:
How did Niels Bohr contribute to the development of the atomic model after Rutherford’s discovery?
Niels Bohr proposed in 1912 that electrons only travel in certain paths or orbits around the nucleus, similar to planets orbiting the sun.
What major discovery about atomic structure was made by James Chadwick in 1932?
James Chadwick discovered neutrons, which showed that the nucleus was made up of positively charged protons and neutrons without any charge.
When did Dalton discover the atomic model?
It was in1803.
Summarise the Planetary Model
Bohr model proposes that the electrons orbit on specific or quantise energy levels and that electrons can move between these quantum states by emitting or absorbing electromagnetic radiation.
What is the best evidence that proves the planetary model?
Hydrogen Spectra – best evidence for the Bohr model came from its ability to explain the Rydberg formula for the hydrogen spectral lines. The discrete lines in the hydrogen spectrum are a direct result of the quantization of energy levels in the atom.
How does de Broglie’s theory relate to the bohr model?
De Broglie’s theory proposes that particles, such as electrons, exhibit both particle-like and wave-like behaviour this explains why electrons do not radiate energy continuously but rather exist in quantized energy states.
What are the limitations of the bohr model?
can’t explain:
* the atomic spectra of atoms heavier than hydrgoen
* the zeeman effect
* the stability of quantuam states
* line splitting
* Change in the intensity of spectral lines in hydrogen
How did JJ Thompson formulate the charge to mass ratio ?
Thomson’s experiment involved manipulating the path of a cathode ray using a uniform electric field and a uniform magnetic field. Thomson’s experiment obtained a value for the charge to mass ratio of cathode rays, which proved their particle nature.
