Orbitals

Saylor Academy14 minutes read

The structure of atoms involves a nucleus with electrons forming a smear around it, not in fixed orbits but as a probability function. Different elements have unique electron configurations based on energy shells, with electrons following specific rules for filling orbitals.

Insights

  • Electrons in an atom are not in fixed orbits but exist as a probability function around the nucleus, described by the Heisenberg uncertainty principle. This challenges the traditional view of electrons moving in predictable paths like planets around a star.
  • The electron configuration of atoms follows a specific pattern based on energy shells denoted by the quantum number 'n', with each shell accommodating a certain number of electrons. This structured filling of orbitals determines an element's chemical properties and behavior.

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Recent questions

  • What is the Heisenberg uncertainty principle?

    It states that the position and momentum of a particle cannot be precisely determined simultaneously.

  • How are electrons described in an atom?

    As a smear around the nucleus due to the Heisenberg uncertainty principle.

  • What is the Bohr model?

    A model conceptualizing electrons as planets around a star.

  • How do electrons move between energy states?

    By absorbing or emitting energy in the form of light waves.

  • What is the electron configuration of lithium?

    1s2 2s1

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Summary

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Atomic Structure and Electron Configurations

  • The nucleus at the center of an atom is a small fraction of the total volume, with electrons described as a smear around it due to the Heisenberg uncertainty principle.
  • Electrons in an atom are not in orbits like planets around the Sun but can be described as a probability function around the nucleus.
  • The 1s orbital is a sphere around the nucleus with no strict boundary, denser towards the center, indicating a higher probability of finding the electron there.
  • The Bohr model, named after Niels Bohr, conceptualizes electrons as planets revolving around a star, useful for understanding energy states.
  • Energy levels in atoms can change, affecting the electron's path, similar to a planet's orbit becoming more elliptical with more energy.
  • Light waves can give energy to electrons, moving them to higher energy states, emitting photons when returning to lower states.
  • Electrons fill different orbitals based on energy shells denoted by the number 'n', corresponding to periods in the periodic table.
  • Hydrogen's electron configuration is 1s1, with one electron in the 1s orbital, shaped like a sphere.
  • Helium's electron configuration is 1s2, with two electrons in the 1s orbital, following the rule of two electrons per subshell.
  • Lithium's electron configuration progresses to 1s2 2s1, filling the 1s orbital with two electrons and moving the third electron to the 2s orbital in the second energy shell.
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