Chapter 2 Flashcards
Atomic Theory
“A” Number
Atomic weight; protons + neutrons
“Z” Number
Atomic number; number of protons
Isotopes
Atoms of the same element with the same number of protons but different number of neutrons. Chemically similar but different masses.
Mass spectroscopy
Identifies isotopes by charge-to-mass ratio through arc analysis
Thompson experiment
Used electric field to determine that charges of protons and electrons are opposite of one another
Millikan experiment
A charged oil drop suspended in an electric field determined the magnitude of charge for protons and electrons are the same
Rutherford experiment
Tried to find e- by shadow; the atom is made up of (mostly) empty space
Excitation
When an atom absorbs energy to move an e- to a higher energy level
Energy of a wavelength
E=hv
Effective nuclear charge
Proton charge - e- repulsion
Net charge on valence e- accounting for nucleus attraction, repulsion from core e- shell, and minimal repulsion from other valence e-
Increases left to right
Radicals
Atoms/molecules with at least one unpaired e-, spinning up, susceptible to a magnetic field
Node
The absence of e- density around a nucleus
n
Shell; n>0
l
Shape of orbital; l<n and 0 or above
mi
Orientation of the orbital; -l to +l
ms
Rotation of e- on axis; +½ or -½
How do e- affect atom size?
Size depends on e-
Cations are smaller than neutral atoms
Anions are larger than neutral atoms
What affects atomic radius?
Radius decreases with increasing Zeff
Radius increases with increasing valence e- shells
Electron affinity
Tendency for an element to gain an e-, increases reduction potential
Forms of photon energy
Light energy
Thermal energy
Mechanical energy
Electrical energy
Photon
Energy released when an e- relaxes back towards its ground state
Fluorescence
Conversion of UV light to visible light, appearing as purple under a UV blacklight
Photoelectric effect
When a photon releases an e-, creasing excess energy as kinetic energy.
