Developing the Atomic Model (GCSE Chemistry)
Looking Forward
Overtime scientists have gathered new experimental data which leads to the development of the atomic model or replacement of the old models used to explain atoms. For instance after the alpha particle scattering experiment there was a change in the atomic model from the ‘plum pudding’ model to the nuclear model.
Worked example: Compare and contrast the plum pudding model with the nuclear model of the atom. (3 marks)
- Compare the structure of each atomic model.
In the plum pudding model, there is a positive sphere with negative charge randomly placed within the sphere. There is no empty space.
In the nuclear model, there is a central positive, tiny nucleus, with mostly empty space and lots of negative charges a long way from the nucleus.
- Compare the masses.
The mass in the plum pudding model is distributed equally throughout the sphere. The mass in the nuclear model is concentrated in the nucleus.
FAQs
→How to make atomic model science project?
When looking at the atomic model, GSCE science projects can range in design. One way to display the atomic model is to make models of the atoms, tracing their development over time from John Dalton’s model, Thompson’s plum pudding model, Rutherford’s model, to the most recent atomic models of Bohr and Chadwick. It is also possible to research the development and create a presentation.
The development of the atomic model can be traced back to 1803, where John Dalton experimented with Atomic Theory, where he proposed that matter was composed of tiny, indivisible, solid spheres which he called atoms and that different elements where made up of different atoms. This continued in 1897, when JJ Thompson created the ‘plum pudding model’. In 1909, Ernest Rutherford proposed that atoms consisted of a tiny, dense, positively charged core or nucleus surrounded by a cloud of negatively charged electrons. In 1920 Niels Bohr proposed that electrons could only exist in shells or orbits at different energy levels around the nucleus. In 1932 Chadwick suggested there must exist another particles in the nucleus along with protons, which would otherwise strongly repel each other. James Chadwick later discovered the neutron.
The atomic model in GCSE chemistry refers to the representation of the structure of an atom and its components, including the nucleus and electrons.
The development of the atomic model is important in GCSE chemistry because it provides a basic understanding of the nature of matter and the behavior of atoms in chemical reactions.
John Dalton’s first atomic model proposed that atoms were indivisible, indestructible particles that were different for each element.
J.J. Thomson’s discovery of the electron in 1897 provided evidence for the existence of negatively charged particles within atoms, which led to the development of the planetary model of the atom.
Ernest Rutherford’s gold foil experiment provided evidence for the existence of a dense, positively charged nucleus in the center of the atom, which led to the development of the nuclear model of the atom.
The current understanding of the atomic model is that atoms consist of a small, dense nucleus containing protons and neutrons, surrounded by electrons in energy levels.
The electrons in the atomic model are negatively charged particles that occupy energy levels around the nucleus. They are involved in chemical reactions and bonding with other atoms.
The nucleus in the atomic model is a small, dense region in the center of the atom that contains positively charged protons and neutral neutrons. It is responsible for most of the atom’s mass and its chemical properties.
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