Chemistry Chp 11&12 Review Flashcards
Exceptions to the Octet Rule
H (wants 2e), Be (wants 4e) and B (wants 6e)
The center atom in a LDS is usually
Carbon
Resonance
Atoms stay put double bonds move (to go from one to the other use double sided arrow)
CH is
nonpolar always
Polarity
determined by electronegativity differences
EN difference of 0–>0.4
Non-polar covalent (equal sharing)
EN difference of 0.5–>1.7
Polar covalent (unequal sharing)
EN difference over 1.7
Ionic (taking)
Bond polarity arrows
–+—> towards more electronegative side
Molecular polarity
Defined by the sum of the bond polarities or symmetry (symmetrical molecules are non-polar)
Water is…
Always polar
IMF definition
the forces between molecules (hold molecules together) They are represented by dashed lines
they have a weak intermolecular attraction
IMFs and Boiling/Melting point
The stronger the IMF bond the HIGHER the Bp/Mp bc you need more energy to break the molecules apart
Types of IMFs
Ion-Dipole (strongest)
Hydrogen Bonding
Dipole-Dipole (polar)
Induced dipole-induced-dipole (non-polar) (weakest)
Ion-Dipole
The interaction between an ion and a polar molecule (the ion is fully charged and the polar molecule is partially charged)