Topic 3. Quantum Mechanics and Atomic Orbitals (1)

Quantum Mechanics

A fundamental theory in physics describing the physical properties of nature at the scale of atoms and subatomic particles.

Atomic Orbital

A mathematical function that describes the wave-like behavior of an electron in an atom.

Isotope

Atoms of the same element with different numbers of neutrons.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Frequency (v)

The number of waves that pass a given point in one second, measured in hertz (Hz).

Wavelength (λ)

The distance between two adjacent peaks (or troughs) of a wave.

Blackbody Radiation

The emission of electromagnetic radiation from an object as a function of its temperature.

Photoelectric Effect

The phenomenon in which electrons are ejected from a material when it is exposed to light of a certain frequency.

Quantum Number

A number that quantizes the values of certain physical properties of particles, such as electrons in an atom.

Principal Quantum Number (n)

Determines the size and energy of an atomic orbital.

Angular Momentum Quantum Number (l)

Defines the shape of an atomic orbital.

Magnetic Quantum Number (m)

Defines the orientation of an orbital in space.

Spin Quantum Number (ms)

Indicates the direction of an electron's spin, with possible values of +1/2 or -1/2.

Aufbau Principle

Electrons fill atomic orbitals in increasing order of their energy levels.

Hund's Rule

Every atomic orbital in a sublevel is singly occupied before any orbital is doubly occupied.

Electron Configuration

The distribution of electrons in an atom's orbitals.

Effective Nuclear Charge (Z_eff)

The net positive charge experienced by an electron in a multi-electron atom.

Atomic Radius

The size of an atom, typically measured as the distance from the nucleus to the outermost electron.

Ionization Energy

The energy required to remove one or more electrons from an atom in its gaseous state.

Electron Affinity

The energy change that occurs when an electron is added to a neutral atom.

Metallic Character

The set of properties associated with metals, including luster, conductivity, and malleability.