The Periodic Table

  s-block                                                  d-block                                                               p-block
1
H
1.008
2
He*
4.00
2
He*
4.00
3
Li
6.94
4
Be
9.01
5
B
10.8
6
C
12.0
7
N
14.0
8
O
16.0
9
F
19.0
10
Ne
20.2
11
Na
23.0
12
Mg
24.3
13
Al
27.0
14
Si
28.1
15
P
31.0
16
S
32.1
17
Cl
35.5
18
Ar
40.0
19
K
39.1
20
Ca
40.1
21
Sc
45.0
22
Ti
47.9
23
V
50.9
24
Cr
52.0
25
Mn
54.9
26
Fe
55.8
27
Co
58.9
28
Ni
58.7
29
Cu
63.5
30
Zn
65.4
31
Ga
69.7
32
Ge
72.6
33
As
74.9
34
Se
79.0
35
Br
79.9
36
Kr
83.8
37
Rb
85.5
38
Sr
87.6
39
Y
88.9
40
Zr
91.2
41
Nb
92.9
42
Mo
95.9
43
Tc
98
44
Ru
101
45
Rh
103
46
Pd
106
47
Ag
108
48
Cd
112
49
In
115
50
Sn
119
51
Sb
122
52
Te
128
53
I
127
54
Xe
131
55
Cs
133
56
Ba
137
57
La*
139
72
Hf
178
73
Ta
181
74
W
184
75
Re
186
76
Os
190
77
Ir
192
78
Pt
195
79
Au
197
80
Hg
201
81
Tl
204
82
Pb
207
83
Bi
209
84
Po
210
85
At
210
86
Rn
222
87
Fr
223
88
Ra
226
89
Ac*
227
104
Ku
105
Ha
106


Notes:

*He, Helium is typically positioned top right in the Periodic Table because it's a noble gas and "belongs" with the other noble gases such as neon and argon. Recall that the noble gases are inert because they are stable which is in turn because they have complete shells. For helium, it's the 1s shell that is full, for the others, it's the p orbital set that is full. That's way in this context, it's fair to put helium on the left side next to hydrogen.

How to use the Periodic Table to determine the order of orbital filling

1. Start from the top left with hydrogen

2. Read across the rows, in order of increasing atomic number.

3. For each element, the colour of the block indicates which orbitals are being filled. This allows you to read off the order of the orbitals....this means the orbital energies list from lowest (most stable) to highest (least stable) and hence the orbital filling order is 1s 2s 2p 3s 3p 4s 3d 4p etc.

Orbital filling based on the periodic table
(this image ignores the lanthanides and actinides in the f-block series)