Inorganic Chem Pre-Exam

Screening/Shielding Effect

Electrons in inner shells of the atom cause the nucleus to have less pull on its valence electrons.

Coulomb Force

the force of attraction or repulsion between two charged particles

Nuclear Charge

Total charge of nucleus (atomic number Z)

Ionization Energy

Amount of energy needed to remove an electron from an atom or molecule. Generally increases as you move towards top right corner.

Ionization Energy Exceptions

First ionization energies for elements in group 15 are higher than their counterparts in group 16 cause the p orbital is half-filled for group 15 (so more stable). For example, N has higher energy than O.

Nodal Planes

Place around an atom where likelihood of finding an electron is zero. n - l - 1. Principal Quantum number - azimuthal quantum number - 1.

VSEPR (Valence Shell Electron Pair Repulsion)

Bonding Orbitals

Molecular orbital in which two orbitals merge (constructive interference) and a bond is formed. Lower energy and more stable.

Antibonding Orbitals

Molecular orbital in which two orbitals cancel each other out (destructive interference). Nodal plane, so no electron density. Higher energy and less stable.

Particle-Wave Duality

Electrons and photons act both as particles and waves.

Einstein Photoelectric Effect

Electrons are emitted from a material when light hits it at a frequency higher than a certain threshold frequency. E = h*f.

Thomson Electron Diffraction

experiments that showed that electrons exhibit wave-like properties by showing they could be diffracted, similar to X-rays

Ruska Electron Microscope

uses a beam of high energy electrons to help magnify very small objects (organelles, viruses, etc)

Millikan’s Oil Drop Experiment

experiment that used charged oil droplets to determine the charge of an electron. found that all charges are multiples of that electron charge.

Ionic Character

difference in electronegativity between two bonded atoms. Greater value means more polarizable

Lewis Acid

Electron acceptor. ex: tranistion metals

Lewis Base

electron donor. ex: ammonia

Coordinate Bond

covalent bond in which both electrons come from one atom. ex: NH₃ shares two electrons with H+ to become NH₄.

Electromagnetic Spectrum

From low to high frequency/radiation: Radio, micro, infrared, visible, ultraviolet, x-ray, gamma. Rich Men In Vegas Use Xpensive Girls

Bohr’s Model

theory that electrons orbit a nucleus of an atom in shells. Higher/farther shells have higher energy.

Valence Bond Theory

unpaired valence electrons of two different atoms merge their atomic orbitals to form covalent bond.x

Degenerate orbitals

Orbitals that have the same energy level. ex: the electron pairs in a 2p⁶ are degenerate to each other. CH₄ has triply degenerate orbitals, not four, because it’s tetrahedral.

Molecular Orbital Theory

Atomic orbitals merge to form molecular orbitals. Bonding (low energy) orbitals fill first, then anti-bonding (high energy) orbitals.

Effective Nuclear Charge

Atomic Number - Shielding Electrons (Z - S)

Electron configuration order

Octet Rule

General rule that atoms gain/lose the minimal amount of electrons to have 8 valence shell electrons

Geometric isomers

Stereoisomers with same chemical formula and connectivity but different spatial arrangement. Like cis-trans isomers.

Optical Isomers

Enantiomers. Same formula, connectivity, but non-superimposable mirror images of each other.

Dimeric structures

molecule formed from two identical chemical units

Gibbs Free Energy

Thermodynamic potential energy. Postive means non-spontaneous, negative means spontaneous. Equal to ΔH - TΔS

Rate laws

describes rate of a chemical reaction in relation to substrate concentrations.

Cis-trans isomers IR spectrum

cis isomers have much stronger signal than trans isomers

Why are there different frequencies for C=O stretches?

Carbonyls connected to EDGs, such as metals acting as Lewis bases, have lower IR frequencies

Particle in a box

A particle confined to a finite space can only have discrete, or quantized, energy levels.