lewis structures and shapes of molecules Flashcards
what are the 3 exceptions to the octet rule ?
radicals (odd number of electrons)
electron poor molecules (less electrons than an octet)
more electrons than an octet
what is the equation for the formal charge
(number of valence electrons from the free atom) - (number of bonds to the atom) - (number of unshared electrons)
what is the maximum CN for B, C, N
4
what is the maximum CN for O
3
what is the maximum CN for F
2
what is the maximum CN for all of period 3
6
what is the maximum CN for period 4,5,6
6,7,8
what does hyper valence mean
when there are more than 8 valence electrons around the central atom
why does NF5 not exist?
- oxidation state of 5 is allowed.
- however CN isn’t
- due to the fact that the nitrogen atom is to small to have efficient overlap with more than four other atoms (ligands).
draw a molecule with 3 bonds and 0 lone pairs
trigonal planar
draw a molecule with 2 bonds and 1 lone pairs
bent
draw a molecule with 4 bonds and 0 lone pairs
tetrahedral
draw a molecule with 3 bonds and 1 lone pairs
trigonanal pyrimidal
draw a molecule with 2 bonds and 2 lone pairs
bent
draw a molecule with 5 bonds and 0 lone pairs
trigonal bipyrimidal
