l2 - orbital theory, electron config & hybridisation Flashcards
1
Q
shape of s orbitals
A
spherical
2
Q
shape of p orbitals
A
dumbell
3
Q
where are s orbitals centred?
A
closest around the nucleus (e.g. 1s on inside, 2s on outside)
4
Q
sp3
A
tetrahedral. 109.5 degrees. all bonds are sigma or ‘single’ = combines the s orbitals and all 3 of the p orbitals.
5
Q
sp2
A
trigonal planar = 120 degrees = 1 s orbital and 2 p orbitals = flat
6
Q
sp
A
linear = 180 = combines the s and p orbitals
7
Q
sigma bonds
A
- strongest covalent bonds
- orbitals overlap
- form with s and p orbitals
- 2e-
8
Q
pi bonds
A
- weaker than sigma bonds
- overlap of 2 orbital lobes on one atom with 2 orbital lobes on another
- node between lobes has no electron density
- pi bonds overlapping
9
Q
lone pairs
A
- paired electrons occupying one or more of the hybridised orbitals
- lone pairs repel more far apart as they are held closer to the atom than the electrons
10
Q
how many lone pairs does nitrogen have?
A
1
11
Q
how many lone pairs does oxygen have?
A
2
12
Q
bond angle of NH3
A
107.3
13
Q
bond angel of H20
A
104.5
14
Q
consequences of orbital hybridisation on molecular shape
A
- methane is sp3 hybridised, tetrahedral shape, 109.5
- ethene’s carbons are sp2 hybridised, 3 sp2 orbitals in one plane, 120
15
Q
can sigma bonds rotate freely?
A
yes leading to isomers
16
Q
can pi bonds rotate freely?
A
no
