Structure of atoms and isotopes

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Particles > Structure, properties and function of elements (periodic table) > Structure of atoms and isotopes 

Atoms have nuclei comprising of protons and neutrons while electrons orbit around the nuclei. Atoms are neutral as they contain equal number of protons and electrons. Isotopes are atoms of the same element differing only in the number of neutrons in their nuclei. Some isotopes are more stable than others.

Connection to Big Idea about energy: The potential energy of an electron that rotates around an atomic nuclei is due to the attractive electromagnetic force between the two objects. When an electron loses a part of its energy one or more photons are emitted with total energy equal to the energy loss of the electron. The nuclear potential energy of the atomic nuclei is released during the nuclear fission of the atom.

Connection to Big Idea about forces: Attractive and repulsive forces are present in atoms. The attractive electromagnetic forces between the protons and electrons keep the latter in orbit around the nuclei while the attractive strong nuclear force between the protons and the neutrons keeps the atomic nuclei bound against the repulsive electromagnetic forces between the protons which tend to destroy the nuclei.

Connection to Big Idea about the universe: In the early Universe particles were combined to form atoms. The elementary particles were combined to form nuclei and then they attracted electrons to form atoms. The formed atoms were these of Hydrogen and Helium. The rest of the atoms that construct our world where made either through the stellar nucleosynthesis or the supernova nucleosynthesis.

Connection to Big Idea about quantum: The structure and properties of atoms are described by quantum mechanics. Bohr was the first to describe the structure of the atom according to which electrons around an atomic nucleus can only orbit at certain discrete set of distances from the nucleus. Nowadays, quantum mechanical models are used to explain more complex atoms.

Connection to Big Idea about Earth: There are isotopes on Earth. The atoms of the same element can vary in the number of neutrons present in their nucleus, like protium, deuterium and tritium for the hydrogen atom (0, 1 and 2 protons). Those variations in protons could be rare for some atoms or very similar on others. A useful application of the Earth’s isotopes is their use for the estimation of the age of rocks, fossils and of the planet itself. 

Subjects related: Chemistry,Physics

Age ranges: 14-15,15-16,16-17,17-18



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