Electron Configuration and Orbital Notation

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Electron Configuration Noun

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[uh-lek-tron kon-fig-yuh-rey-shuhn]

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Electron Configuration

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The specific arrangement and distribution of electrons within the various orbitals of an atom in its ground state.

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Example: This Bohr model for a Sodium atom shows its electron configuration: 2 electrons in the first shell, 8 in the second, and 1 in the outer shell.

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Bohr Model Noun

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[bor mod-l]

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Bohr Model

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A simplified atomic model depicting electrons orbiting the nucleus in fixed, circular paths called energy levels or shells.

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Example: This diagram shows a Bohr model, where electrons orbit a central nucleus in specific energy shells, illustrating a basic form of electron configuration.

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Quantum Mechanical Model Noun

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[kwon-tuhm muh-kan-i-kuhl mod-l]

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Quantum Mechanical Model

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An atomic model describing an electron's location as a probability cloud, indicating the region where it is most likely found.

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Example: This diagram shows the quantum mechanical model of an atom, where electrons exist in a 'cloud' of probable locations around the nucleus, not in fixed orbits.

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Principal Energy Level Noun

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[prin-suh-puhl en-er-jee lev-uhl]

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Principal Energy Level

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The main energy level of an electron, denoted by 'n', indicating its relative distance and energy from the nucleus.

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Example: This diagram shows an atom's electrons orbiting the nucleus in distinct paths called electron shells, which represent the principal energy levels.

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Sublevel Noun

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[suhb-lev-uhl]

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Sublevel

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A division within a principal energy level corresponding to orbital shapes, denoted by the letters s, p, d, and f.

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Example: This image shows the three parts, called orbitals, that make up a p-sublevel. Each orbital has a different shape and orientation in 3D space.

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Atomic Orbital Noun

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[uh-tom-ik awr-bi-tl]

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Atomic Orbital

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A specific region within a sublevel where there is a high probability of finding an electron, holding a maximum of two.

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Example: This image contrasts the outdated Bohr model of an atom with modern atomic orbitals, showing that orbitals are not circular paths but specific 3D shapes.

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Aufbau Principle Noun

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[ouf-bou prin-suh-puhl]

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Aufbau Principle

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The rule stating that electrons must occupy the lowest energy orbitals available before filling any higher energy orbitals.

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Example: This diagram shows the order for filling electron orbitals, from lowest energy to highest. Follow the diagonal arrows to find the correct sequence.

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Pauli Exclusion Principle Noun

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[pou-lee ik-skloo-zhuhn prin-suh-puhl]

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Pauli Exclusion Principle

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The principle that an atomic orbital can hold a maximum of two electrons, and these two electrons must have opposite spins.

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Example: This diagram shows that for two electrons to share an orbital (box), they must have opposite spins, represented by one arrow pointing up and one down.

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Hund's Rule Noun

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[huhnds rool]

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Hund's Rule

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The rule that electrons will singly occupy each orbital of equal energy before any orbital is doubly occupied.

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Example: The image shows that electrons (arrows) fill empty orbitals (boxes) one at a time before pairing up, demonstrating Hund's rule through sequential element examples.

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Electron Spin Noun

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[uh-lek-tron spin]

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Electron Spin

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An intrinsic quantum property of an electron creating a magnetic moment, conventionally described as 'spin up' or 'spin down'.

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Example: An electron's spin creates a tiny magnetic field, which can point in one of two opposite directions, represented as 'spin up' (+1/2) or 'spin down' (-1/2).