| 1A | 2A | 3A | 4A | 5A | 6A | 7A | 8A | ||||||||||||
| (1) | (2) | (13) | (14) | (15) | (16) | (17) | (18) | ||||||||||||
| 3B | 4B | 5B | 6B | 7B | — | 8B | — | 1B | 2B | ||||||||||
| (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) | (11) | (12) | ||||||||||
| 1 |
H xx |
He xx |
|||||||||||||||||
| 2 |
Li xx |
Be xx |
B xx |
C xx |
N xx |
O xx |
F xx |
Ne xx |
|||||||||||
| 3 |
Na xx |
Mg xx |
Al xx |
Si xx |
P xx |
S xx |
Cl xx |
Ar xx |
|||||||||||
| 4 |
K xx |
Ca xx |
Sc xx |
Ti xx |
V xx |
Cr xx |
Mn xx |
Fe xx |
Co xx |
Ni xx |
Cu xx |
Zn xx |
Ga xx |
Ge xx |
As xx |
Se xx |
Br xx |
Kr xx |
|
| 5 |
Rb xx |
Sr xx |
Y xx |
Zr xx |
Nb xx |
Mo xx |
Tc xx |
Ru xx |
Rh xx |
Pd xx |
Ag xx |
Cd xx |
In xx |
Sn xx |
Sb xx |
Te xx |
I xx |
Xe xx |
|
| 6 |
Cs xx |
Ba xx |
La xx |
Hf xx |
Ta xx |
W xx |
Re xx |
Os xx |
Ir xx |
Pt xx |
Au xx |
Hg xx |
Tl xx |
Pb xx |
Bi xx |
Po xx |
At xx |
Rn xx |
|
| 7 |
Fr xx |
Ra xx |
Ac xx |
Rf xx |
Db xx |
Sg xx |
Bh xx |
Hs xx |
Mt xx |
Ds xx |
Rg xx |
Uub xx |
— |
Uuq xx |
— |
— |
— |
— |
|
| 6 |
Ce xx |
Pr xx |
Nd xx |
Pm xx |
Sm xx |
Eu xx |
Gd xx |
Tb xx |
Dy xx |
Ho xx |
Er xx |
Tm xx |
Yb xx |
Lu xx |
|||||
| 7 |
Th xx |
Pa xx |
U xx |
Np xx |
Pu xx |
Am xx |
Cm xx |
Bk xx |
Cf xx |
Es xx |
Fm xx |
Md xx |
No xx |
Lr xx |
There are a number of important physical and chemical properties of the elements that vary in a periodic way across the periodic table. For example, elements in Group 1A all tend to participate in similar chemical reactions with water,
2M(s) + H2O(l) ® MOH(aq) + H2(g)
as do the Group 2A elements,
M(s) + 2H2O(l) ® M(OH)2(aq) + H2(g)
while the Group 7A elements all form -1 charges in ionic compounds and diatomic molecules in their elemental state, the group 8A elements are all inert monatomic gases, and so on. Elements in the same group tend to have the same electron configurations for their valence shells, and so they tend to participate in similar chemical reactions and form similar compounds because they all satisfy the octet rule the same way. (For more information on this, see the section on Electron Configuration.)
There are a number of properties of the elements whose relative magnitudes can be predicted using the periodic table, because they vary in a (more-or-less) predictable way. These include the sizes of atoms and ions, ionization energy, electron affinity, and electronegativity. A summary of the trends in each property is included on this page.