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Atomic Orbitals

An electron is considered to be a cloud of negative charge that fills a volume in space called an atomic orbital.Each orbital has a different energy level and a different shape that represents a region in space where there is a 95% probability of finding an electron.Electrons are arranged within shells around the nucleus. The shells are regarded as energy levels. Each energy level has a principal quantum number n = 1, 2, 3, 4, 5, 6, 7 with the shell n = 1 with the lowest energy and closest to the nucleus.
Electrons have properties of both waves and particles. The maximum number of electrons in a shell is given by 2n2. Each shell is subdivided into s, p, d or f sub-levels with slightly different energies. The sub-levels in the first four quantum shells are 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f. The electron occupies a region in space called an orbital
An orbital is a region in space where there is a 95% chance of finding the electron. An orbital can hold up to two electrons with opposite spin.

An electron can be thought of as a cloud with the shape of an orbital called an electron cloud. There is one type of s orbital, three types of p orbital (px,py,pz ) with different orientations, five types of d orbitals and seven types of f orbitals each having a different shape.
sub-shellnumber of orbitals
s1
p3
d5
f7

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Specification: AQA Chemistry (7404), AS-level, 3.1.1.3 Electron configuration. Topic: Atomic Structure.

Key terms in this lesson

Principal quantum number
The number (n = 1, 2, 3...) given to an electron shell, indicating its energy level and distance from the nucleus.

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