Exam 3 Review Flashcards
Electromagnetic Radiation
type of energy described by a wave composed of oscillating electric and magnetic field
Speed of light in vacuum (c)
3x10^8 m/s
frequency (curvy v)
number of wave crests or cycles that travel through a stationary point in a given amount of time (measured in cycle per second, s^-1, or Hz)
Velocity (flat v)
flat v = (wavelength)(frequency)
Vacuum (flat v) = speed of light (c)
c= (wavelength)(frequency)
Electromagnetic Spectrum (in term of largest wavelength to shortest wavelength)
radio wave<microwave<infrared wave< visible light<ultraviolet wave<x-ray< gamma ray
Interference
superposition of 2 or more waves overlapping in space resulting in either increase or decrease of amplitude
Constructive Interference
2 waves overlap with each other making a new higher frequency wave
Destructive Frequency
2 waves (where the crest aligns with the trough) lowering the amplitude
photon
massless particle of light
Planck’s Constant
h = 6.626x10^-34 Js
Ephoton
= (hc)/(wavelength)
En (energy associated with each level in a H atom)
En = (-2.18x10^-18J)/(n^2)
Change in energy between 2 levels in H atom
Delta H - E final- E initial
-2.18x10^-18(1/nf^2-1/ni^2)
delta E > 0
a photon is absorbed to excite the electron to higher level (absorb energy)
delta E < 0
a photon is released and electron relaxes to lower energy level (release energy)
Orbital
represents a probability distribution map that shows where an electron is likely located
principle quantum number
n –> principle shell/level, general region of electron
angular momentum quantum number
l –> subshell, shape of the orbital
magnetic momentum quantum numbers
Ml (2(l) + 1) –> orientation of the orbital
spin quantum number
ms (-1/2, 1/2) –> direction of “spinning” electron
phase
the sign of the amplitude of a wave (positive or negative)
spin quantum number (Ms)
a half-integer value that denotes the “spin” of the electron (-1/2,1/2)
Orbital Diagram
symbolizes electron as arrows and the orbital as a line or a box
Pauli Exclusion Principle
no 2 electrons is an atom cannot have the same set of four quantum number
-the arrows go in the different directions in the same box
Shileding
the effect of an electron of repulsion by electrons in lower energy will shield it from the full effects of nuclear charge
Effective Nuclear Charge (Z eff)
actual nuclear charge that is experienced by the electron
Aufoam Principle
electrons fill lower energy orbitals first before filling higher orbitals
needs to fill up 1s^2 2s^2 then 2p^1
valence electrons
the electrons in the outermost shell
core electrons
all other elements not in the outermost shell
paramagnetic
the state of an atom or ion that contains unpaired electrons (they are attracted to an external magnetic field)
diamagnetic
the state of an atom or ion that contains all electrons are paired (they are not attracted to an external magnetic field)
Atomic Radius
increases going down and decreases going from left to right
Cations
much smaller than their neutral atom counterpart
Anions
much larger than their neutral atom counterpart
Isoelectronic
atoms or ions that have the same EC
Metallic Charges
increases top to bottom and decreases from left to right
ionization energy
the energy required to remove electron from an atom or ion in the gaseous state (decreases top to bottom and increases left to right)
Electron Affinity
the energy change associated with the gaining of an electron by an atom or anion in a gaseous state (decreases top to bottom and increases left to right)
Octet Rule
the tendency of atoms of most main-group elements to posses or share 8 electrons in their outermost shell to obtain a stable EC (that of the nearest noble gas)
EXCEPT for H, He, Li ( they follow duet rule)
Electronegativity
refers to the ability of an atom to attract electrons toward itself in a chemical bond
Resonance Structure
lewis structure of a molecule or polyatomic ion that differ only int he position of their electrons
Bond Order Formula
(number of bonds around central atoms)/(number of terminal atoms)
formal charge
the charge an atom would have if all bonding electrons are shared equally between other atoms
FC Formula
(number of valence electrons)- 1/2(number of bonding electrons)-(number of non bonding electrons)
Properties of ionic compounds
-solid at room temperature
-high mp and bp
-good conductor of electricity when dissolved in water
Properties of molecular compounds
-liquid or gas at room temperature
-low mp and bp
-poor conductor of electricity when dissolved in water
Hund’s Rule
every orbital in a subshell is singly
occupied with one electron before any one orbital is doubly occupied
-all the arrows are fulled up in the boxes first before the down arrows occur
