Quantum Mechanical Model of the Atom

Quantum Mechanical Model of the Atom

• The quantum mechanical model describes the behavior of electrons in atoms.
• Electrons do not orbit the nucleus in fixed paths, but exist in regions called orbitals.
• An orbital is a region around the nucleus where there is a high probability of finding an electron.
• Atomic orbitals have different shapes, sizes, and energies.
• The four fundamental types of atomic orbitals are s, p, d, and f.
  • s orbitals are spherical.
  • p orbitals are dumbbell-shaped.
  • d orbitals have more complex shapes.
  • f orbitals are the most complex.
• The different shapes, sizes, and energies of orbitals are described using quantum numbers.

Objectives

• Describe atomic orbitals (s, p, d, f).
• Describe the quantum model of an atom.
• Describe electron behavior using quantum numbers and electron configuration.
• Explain the importance of electron configuration and quantum numbers in describing atoms.
• Illustrate electron configuration and orbital diagrams of elements.

Chance of Finding an Electron in the Nucleus

• The probability of finding an electron in the nucleus is very low.

Erwin Schrödinger and Louis de Broglie

• They proposed that electrons possess wave-like properties.
• Schrödinger used mathematics to develop a model of the atom, focusing on the hydrogen atom.
  • This model described the probability of locating an electron.

Quantum Mechanical Model

• Electrons exist as a cloud-like region rather than fixed paths (orbits)
• Different probabilities determine an electron's possible locations in this cloud.

Electron Configuration

• Electron configuration: a representation of electron distribution in orbitals.
• Electron configuration describes the probability distribution of electrons around the atom's nucleus.
• It is used for a shorthand representation of orbitals, sub-levels, and levels where electrons are located.

Mnemonic

• A mnemonic device aids in remembering information by creating patterns.

Rules for Electron Location

• Pauli Exclusion Principle: A maximum of two electrons can occupy one orbital, and they must have opposite spins.
• Hund's Rule: Electrons fill orbitals singly before they pair up. If a set of orbitals is available, each orbital will be occupied by one electron with spins in the same direction before it is occupied by a second electron with an opposite spin direction.
• Aufbau Principle: Electrons first fill the lowest energy levels available. Thus, electrons fill lowest energy levels first before higher energy levels.

Paramagnetism and Diamagnetism

• Paramagnetism: Substances with unpaired electrons are attracted to magnetic fields.
• Diamagnetism: Substances with all paired electrons are weakly repelled by magnetic fields.

Aufbau Principle

• Electrons first fill the lowest energy orbitals available.

Quantum Numbers

• Set of numbers used to describe the position and energy of electrons.
  • Principal Quantum Number (n): The main energy level of an electron (n = 1, 2, 3...).
  • Azimuthal Quantum Number (l): Describes the shape of an electron's orbital (l = 0 to n-1; s=0, p=1, d=2, f=3).
  • Magnetic Quantum Number (ml): Describes the orientation of an orbital in space (-l to +l).
  • Spin Quantum Number (ms): Describes the spin of an electron (+1/2 or -1/2).

Explore the intricate details of the quantum mechanical model of the atom, including the behavior of electrons and the various types of atomic orbitals (s, p, d, f). This quiz will help you understand quantum numbers and the significance of electron configuration. Test your knowledge on these fundamental concepts in atomic theory.