Effective Nuclear Charge

Effective Nuclear Charge (Zeff)

The net positive charge experienced by valence electrons, calculated as Zeff = Z - S, where Z is the total number of protons and S is the number of core electrons.

Atomic Radius

Half the distance between the nuclei of two atoms in a molecule, representing the size of an atom.

Core Electrons

Electrons that are located in the inner shells of an atom, not involved in bonding.

Valence Electrons

Electrons found in the outermost occupied orbitals of an atom, which participate in forming chemical bonds.

Coulomb’s Law

A formula that describes the electrostatic interaction between electrically charged particles, represented as F = k(q1q2)/r².

Screening Effect

The phenomenon in which core electrons shield valence electrons from the full effect of the nuclear charge.

Periodic Trends

Patterns in the periodic table that show changes in properties such as atomic radius, ionization energy, and electronegativity.

Electrostatic Force

The attractive or repulsive force between charged particles, governed by Coulomb's law.

Quantum Mechanical Model

The modern description of the behavior of electrons in atoms, which incorporates wave-particle duality.

Atomic Radius Down a Group

Atomic radius increases down a group due to the addition of electron shells.

Atomic Radius Across a Row

Atomic radius decreases across a row due to increasing effective nuclear charge, which pulls electrons closer to the nucleus.

Electron Configuration

The distribution of electrons in an atom's orbitals, described using notations such as 1s², 2s², etc.

Condensed Electron Configuration

A simplified notation that shows the electron configuration of an atom using the symbol of the nearest noble gas.

Chemical Behavior

The ways in which atoms interact and bond with one another, largely determined by their valence electrons.

Electrostatic Attraction

The force that draws oppositely charged particles together, important in the interaction between protons and electrons in an atom.

Ionization Energy

The energy required to remove an electron from an atom in the gaseous state.

Atomic Size

The measure of the distance from the nucleus of an atom to the outermost electron.

Electron Shielding

The reduction of the effective nuclear charge on an electron in an atom, caused by other electrons.

Group vs Period in the Periodic Table

A group is a column in the periodic table, while a period is a row.