Electron Structure Flashcards

Electron Structure and Orbital Concepts

• Bromine is a p-block element because its outermost electrons are located in p-subshells.
• The electron configuration of Chromium (Cr) is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵, while that of its Cr³⁺ ion is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³.

Orbitals and Their Shapes

• An orbital can accommodate a maximum of two electrons that have opposite spins.
• s orbitals have a spherical shape, holding a total of two electrons; p orbitals have a dumbbell shape, with each orbital capable of holding two electrons.

Subshells and Electron Capacity

• The s subshell contains one orbital (2 electrons), the p subshell has three orbitals (6 electrons), and the d subshell consists of five orbitals (10 electrons).
• An f subshell has seven orbitals and can hold up to 14 electrons.

Principles of Electron Configuration

• Aufbau's Principle states that electrons occupy orbitals in order of increasing energy levels.
• According to Hund's Rule, electrons will fill orbitals of the same energy singly before pairing in order to minimize repulsion.

Relative Energy of Orbitals

• The 1s subshell has the lowest energy level, followed by the 2s and 2p subshells.
• Within the third shell, the 3s subshell is filled first, followed by 3p.
• The 4s subshell is filled before the 3d subshell, subsequent filling order is 4p, then 4d, and finally 4f.

Classification of Elements

• The s-block elements include the first two groups of the periodic table, along with hydrogen and helium.
• The p block comprises groups 3 to 0, excluding helium.
• The d block consists of transition metals.