Atom Test Flashcards
Wave particle duality
Electrons have both wave like and particle like properties. Moves like a wave with spread out energy but deposits energy at one point.
Particle
Definite trajectory or path on which location and linear momentum are specified at each instant.
Photoelectric effect
Ejection of electrons from metal when metal surface is exposed to UV radiation
-radiation needs frequency above threshold (photon radiation intensity does not matter)
-KE of ejected electron increases linearly with frequency of radiation
Quantized Energy
Electrons can only possess discrete units of energy. Difference in energy between two energy levels is quantized.
Aufbau Principle
Electrons fill lower energy orbitals first before higher energy orbitals
Pauli Exclusion Principle
No two electrons can have the same set of quantum numbers. Electrons in an orbital must have opposite spins.
Hund’s Rule of Maximum Multiplicity
Electrons with parallel spin have to fill every orbital before doubling up in order to minimize e- repulsion’s. Electrons must have paired spins.
Inert Pair Effect
Tendency of certain atoms to form cations with charges of two units lower than would be expected from the atom’s periodic table number. S-electrons have strong penetration abilities (low in energy) so they remain attached. Inner d shells have poor shielding abilities.
NGC
Ends in np6
Pseudo NGC
Ends in nd10
MEER
Ends in nd5
Spin magnetic quantum number
Up: counterclockwise
Down: clockwise
Stern Gerlach Experiment
Shot narrow stream of silver atoms (one unpaired electron) through container with highly non uniform magnetic field. Observed two different spin states for silver atom. (Confirms electron has spin and spin orientation)
Electron Paramagnetic Resonance
Experimental technique used to prove the structure and reactivity of molecules and ions that have unpaired electrons. Detects amount of energy needed to flip electron between its two spin orientations.
Paramagnetism
Tendency of substance to move into magnetic field. Arises when there is at least one unpaired electron. Electrons are randomly aligned so it is weak.
Ferromagnetism
Occurs when unpaired electrons align after external magnetic field applied. Adjacent unpaired electron spins become aligned into large domains.
Domains
Regions of aligned electron spins in a ferromagnetic material that survive after applied magnetic field is removed
Ferromagnetic materials
Iron, cobalt, fe3o4 magnetite. Electrons spin in same direction and have strong magnetic field
Permanent magnets
Made by ferromagnetic materials
Anti ferromagnetic material
Neighboring electron spins locked in anti parallel arrangement so magnetic moments cancel.
Ferrofluids
Suspensions of magnetite in mineral oil. Magnetite form micelles. Oil holds them in place.
D block metal cations
Paramagnetic D-block metal cations form aqueous colorful solutions because they absorb visible light that facilitate electronic transitions for unpaired d-block electrons
Guoy Balance
Examined magnetic character of a sample
Guoy balance results
Prep: sample hung so it lies partially between two poles of electromagnet. Applied magnetic field turned on
Paramagnetic: sample appears to weigh more because it is drawn into field
Diamagnetic: sample pushed out of the field. Appears to weigh less
Free radical
Reactive species with odd number of electrons that is always paramagnetic
Dfs overlay
Energy gaps between shells decrease as n gets larger. D and f approach each other.
Cation orbital energy sequences
The s electrons disappear and dfs overlay region disappears. If more electrons are removed the inter shell gap increases.
