Chem 1021

Mass spectrometry

Analytical technique where the sample is ionized and components identified by measuring the mass to charge ratio

Isotopes

A form of element with same number of protons but different number of neutrons in its nucleus

Electronic energy

Energy of an electron in hydrogen atom

Spectroscopy

Study/measurement of spectra produced when matter interacts with electromagnetic radiation (light)

Transmittance

Measure of how much light passes through sample without being absorbed (fraction/percent)

Absorbance

Measure of how much light a sample absorbs

Will plot vs wavelength in a UV-vis spectrum

Nodes

• area of 0 electron density

• Total number of nodes is n-1

• angular and radial

Phasing - nodes

If the graph has ± values in that area,

Represented by shading

Radial nodes

Not the same as angular nodes - directly related to quantum number

• spherical planes that exist at some radial distance from nucleus

• Appear in 2D cross sections as concentric circles around nucleus

Electron configuration

How many electrons in each orbital & which are occupied

• often based on element in gas phase

• Once multiple electrons are in system, spdf orbitals shift in energy

Degenerate sets

Orbital sets with same energy

Aufbau principle

Start filling at lowest energy level

Hunds rule

Bus rule - adding 1 electron before doubly occupied

Pauli exclusion

If 2e- in same orbital - 1 has to be spin up and one spin down

Paramagnetic

At least one unpaired e-, interacts with mag field

Diamagnetic

All e- are paired, doesn’t interact with mag field

Isoelectronic

Have the same number of electrons

Ionization Energy

Amount of energy required for atom to lose one e-

Electron affinity

Amount of energy released when an e- is gained