Quiz 3/Exam 3 - CH 6-8 Flashcards
Electromagnetic radiation
A form of energy that travel through space as wav s that move at the speed of light
Speed of light
3.0 x 10^8 m/s
Wavelength, y upside down
Distance between two corresponding points on a wave, using meters
Frequency, v
A measure of the number of wave cycles that move through a point in space in 1 second, units are hertz (Hz)
Inversely proportional
Wavelength and frequency
Frequency and wavelength formula
C = yv, c is speed of light
Energy of light
E photon = hv = hc/y
Planck’s constant
6.626 x 10^-34 Js
Energy of a photon is
Directly proportional to the frequency, inversely proportional to the wavelength
Orbitals
Three-dimensional regions in space where electrons are 95% likely to be found
Orbital quantum number (sublevel) l
S: spherically shaped, p: dumbbell shaped, d: 4 lobes, f: 8 lobes
Aufbau principle
Electrons fill orbitals starting with the lowest-energy orbitals
Pauli exclusion principle
A maximum of two electrons can occupy each orbital and must have opposite spins
Hund’s rule
Electrons are distributed into orbitals of identical energy (same sublevel) in such a way as to give the maximum number of unpaired electrons
Valence electrons
Electrons that occupies the valence shell, which is the outer most orbitals in the last-filled (highest n number) principal energy level (S and p for main-group)
Trends in atomic size
Decrease from left to right, increase from top to bottom
Ionization energy
Increased from left to right
Cations are smaller than
Their neutral atoms
More protons
Smaller nucleus
Radius
Increases top to bottom, decreases left to right
Ionization/energy
Increases left to right, decreases top to bottom
Electronegativity
Ability to attract electrons from other atoms (nucleus)
Electronegativity activity
Decreases left to right, decreases top to bottom, does not apply to noble gases
Highest electronegativity
Fluorine
Lowest electronegativity
Frantium
Chemical bond
A force that holds atoms together in a molecule or compound
Ionic bond
Cation and anion, electrostatic between oppositely charged ions, transfer of electrons between cation (metal) and anion (nonmetal)
Covalent bonds
Bond between nonmetals by sharing of electrons between atoms
Non polar covalent
Equal electron sharing
Polar covalent
Unequal electron sharing, the one with higher electronegativity will pull electrons towards it
The greater the difference in electronegativity
The greater the ionic character and
Aufbau’s principle
Electrons fill orbitals starting with the lowest-energy orbitals
Pauli exclusion principle
A maximum of two electrons cna occupy each orbital and must have opposite spins
Hund’s rule
Electrons are distributed into orbitals of identical energy (same sublevel) in such a way as to give the maximum number of unpaired electrons
Ionic bond
Between oppositely charged ions, cation and anion (metal and nonmetal), extremely strong
Covalent bond
Nonmetal and nonmetal
Non polar covalent bond
Equal electron sharing, typically longer bonds, weaker, no difference in electronegativity
Polar covalent bonds
Unequal electron sharing, typically shorter bonds, stronger
The greater the difference in electronegativity
The greater the ionic character and the more polar the bond that joins the atoms
Covalent bonding: Lewis structures
- Count total valence electrons 2. Use 6N + 2 to determine the number of bonds (N is number of non-hydrogen atoms) if 6N + 2= VE, single bonds, if = VE + 2, 1 DB, if = VE + 4, either 2 DB or 1 TB
Resonance
When a molecule can have more than one Lewis structure while only moving electrons (when the structure can be written in more than one way)
Parent structures and angles
2 pairs = linear and 180°, 3 pairs = trigonal planar and 120°, 4 pairs = tetrahedral and 109.5°
Molecular shapes from parent structures : trigonal planar
Trigonal planar = 3 bonded, 0 unbonded, bent = 2 bonded, 1 unbonded
Molecular shape from parent structure : tetrahedral
Tetrahedral = 4 bonded, 0 unbonded, trigonal pyramidal = 3 bonded, 1 unbonded, bent = 2 bonded, 2 unbonded
How to determine a molecule is polar
Have lone pairs or outside atoms are not the same
