Electronic Structure and Periodic Properties of Elements

These flashcards cover key terms and concepts related to the electronic structure and periodic properties of elements as discussed in the lecture notes.

Electromagnetic Energy

A form of energy that travels through space and manifests as light and electromagnetic waves.

Bohr Model

A model of the atom that describes electrons orbiting the nucleus in fixed paths or energy levels.

Quantum Theory

A theory in physics that describes the behaviour of matter and energy at small scales, primarily related to the quantization of energy.

Waves

Periodic disturbances that transfer energy through space and matter.

Speed of Light (c)

The speed at which electromagnetic waves propagate through a vacuum, approximately 2.998 \times 10^8 m/s.

Wavelength (λ)

The distance between two consecutive peaks of a wave, inversely related to frequency.

Frequency (ν)

The number of waves that pass a point in a given time period, typically measured in hertz (Hz).

Planck's Constant (h)

A fundamental constant that relates the energy of photons to their frequency, valued at 6.626 \times 10^{-34} J·s.

Photoelectric Effect

The emission of electrons from a material when it is illuminated by light of sufficient frequency.

Wave-Particle Duality

The concept that every particle or quantum entity may be described as either a particle or a wave.

Heisenberg Uncertainty Principle

A fundamental limit to the precision with which certain pairs of physical properties, like position and momentum, can be known simultaneously.

Atomic Orbital

A mathematical function that describes the probability of finding an electron in a certain region of an atom.

Electron Configuration

The distribution of electrons among the various orbitals of an atom.

Valence Electrons

The electrons located in the outermost shell of an atom that are responsible for chemical bonding.

Ionization Energy

The amount of energy required to remove an electron from an atom in its gaseous state.

Electron Affinity

The change in energy of a neutral atom when it gains an electron to form a negatively charged ion.

Covalent Radius

Half the distance between the nuclei of two identical atoms when they are covalently bonded together.

Isoelectronic Species

Atoms or ions that have the same electron configuration.

Effective Nuclear Charge (Zeff)

The net positive charge experienced by valence electrons after accounting for shielding from inner electrons.

Photon

A quantum of electromagnetic radiation, considered a particle of light.

Energy of a Photon

The energy of a single photon is directly proportional to its frequency, expressed by the equation E = h\nu, where h is Planck's constant and \nu is frequency.

Quantum Numbers

A set of four numbers (n, l, ml, ms) that describe the unique quantum state and properties of an electron in an atom.

Aufbau Principle

States that electrons fill atomic orbitals of the lowest available energy levels before occupying higher energy levels.

Pauli Exclusion Principle

States that no two electrons in the same atom can have identical values for all four of their quantum numbers.

Hund's Rule

States that every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin.

Electronegativity

A measure of the tendency of an atom to attract a bonding pair of electrons in a chemical bond.

Atomic Radius

Half the distance between the nuclei of two unbonded atoms in a crystal lattice or molecule.

Electron Shell

A principal energy level of electrons surrounding the nucleus of an atom, denoted by the principal quantum number (n).

Electron Subshell

A subdivision of an electron shell, composed of one or more atomic orbitals, denoted by the azimuthal quantum number (l).