Bonding Flashcards
Atom
Smallest particle that characterizes a chemical element
Octet Rule
When bonds form between atoms, the atoms gain, lose, or share electrons in a way that they create outer energy levels w/ 8 electrons
Bonding occurs when….where….why…
Valence electrons are shared or transferred at the highest energy level to make it more stable
- Electrons in lower energy lvls are not involved w/ bonding
Define orbitals
Space around an atoms nucleus where an electron may exist
Define Valence Orbitals
Volume of space that can be occupied by electrons in atoms highest energy lvl (outer layer)
Define Bonding Electrons
Un-paired electrons that can be shared w/ other atoms
Define Lone Pair
Two electrons occupying same orbital
Define Valence Electrons
Electrons in highest energy lvl in atom
Define Ionic Bond
Attraction between pos. and neg. ions resulting in transfer of one or more valence electrons
Define Covalent Bond
Two or more electrons are shared among the atoms
Which bond is stronger, (covalent or ionic)
Ionic is stronger
Define Electronegativity
Ability of atom to attract pair of bonding electrons in valance lvl
- Increase as you go up or right of the periodic table
Define Non-polar Molecule
A molecule w/ symmetrical electron distribution
NOTE: Hydrocarbons are always non-polar
Define Polar Molecule
Molecule in which negative charges are not distributed symmetrically among atoms causing partial negative and partial positive charge on both sides of atom
Electronegativity for ionic compound
Difference in electronegativities is usually greater than 1.7 causing electrons to be transferred.
Difference in Electronegativity (DEN)
DEN = 0 - Nonpolar covalent bond
DEN between 0.1-1.7 - Polar Covalent bond
DEN between 1.7-4 - Ionic bond
Bond Dipole
When arrow points towards more electronegativity end of compound
Define Intramolecular Forces
- Forces within the molecule
- Responsible for physical behaviour of molecule substance
What are the two types of intramolecular forces?
- Ionic Bonds: within crystal lattice
2. Covalent Bonds: within a molecule
Define Intermolecular Forces
- Forces between molecules
- Responsible for physical properties in molecules
- Present between covalent compunds
Types of Intermolecular Forces
- Van der Waals Forces
- London Dispersion Forces
- Dipole-Dipole Forces - Hydrogen Bonding
London Dispersion Forces
- Always present between all molecules, does not matter if there are different attractions
- Any electron movement within molecule can produce momentary dipole
- Force gets stronger as # of electrons in molecule increases
- More electrons = more LDF
Relationship between Boiling point and Intermolecular bonds
- Stronger LDF = greater strength of intermolecular forces
- Greater strength of intermolecular forces = higher BP of substance
Dipole - Dipole Forces
- Exist between polar bonds ONLY
- Strength of Dipole force is dependent on overall polarity, more polar = greater DD force
Hydrogen Bonding
- Strongest intermolecular force
- Only occurs when hydrogen bonds to: Oxygen, Nitrogen, or Fluorine
- Must have at least one lone pair
Intermolecular forces of non-polar molecule, polar molecule, and polar molecule w/ H bonded w/ N,O, F
Non-polar = LDF
Polar = LDF, DD
Polar w/ H bonded N,O, F = LDF, DD, HB
List the strengths of attractions for intermolecular and intramolecular forces (weakest to strongest)
- LDF
- DD
- HB
- Covalent Compounds
- Ionic compunds
What does VSEPR stand for
Valence Shell Electron Pair Repulsion Theory
Shape of AXE3 and polarity
- Linear
- 2 Atoms are the same = non polar
- 2 atoms are different = polar
Shape of AX2 and polarity
- Linear
- Peripheral atoms are same = non polar
- Peripheral atoms are different = polar
Shape of AX2E2 and polarity
- V- shaped
- Central atom has lone pairs = polar
Shape of AX3E and polarity
- Trigonal Pyramidal
- Central atom has lone pairs= polar
Shape of AX4 and polarity
- Tetrahedral
- Peripheral atoms are same = non polar
- Peripheral atoms are different = polar
Shape of AX3 and polarity
- Trigonal Planar
- Peripheral atoms are same = non polar
- Peripheral atoms are different = polar