Shapes and Orientations of

Orbitals

Periodic table arrangement

• the quantum theory helps to explain the structure of the periodic table.

• n - 1 indicates that the d subshell in period 4 actually starts at 3 (4 - 1 = 3).

s (n) d (n - 1) p (n)1234567

f (n -2)

• The location of electrons is described by: n, l, ml

n = size, l = shape, ml = orientation

Electron clouds

• The “probability” of finding an electron around a nucleus can be calculated.

• Relative probability is indicated by a series of dots, indicating the “electron cloud”.

• 90% electron probability/cloud for 1s orbital (notice higher probability toward the centre)

p orbitals and d orbitalsp orbitals look like a dumbell with 3 orientations: px, py, pz (“p sub z”). Four of the d orbitals resemble two dumbells in a

clover shape. The last d orbital resembles a p orbital with a donut wrapped around the middle.

4s

3s

2s

1s

2p

3p

3dEENNEERRGGYY

n l ml ms

1 0(s)

2 0(s)1(p)

0

0-1, 10,

3 0(s)1(p)

0-1, 10,

2(d) -1, 1,

0,-2, 24 0(s) 0

Movie: periodic table of the elements: t10-20