Group 12 in the periodic table | |||||||||||
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↓ Period | |||||||||||
4 |
Zinc (Zn) 30 Post-transition metal |
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5 |
Cadmium (Cd) 48 Post-transition metal |
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6 |
Mercury (Hg) 80 Post-transition metal |
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7 |
Copernicium (Cn) 112 Post-transition metal |
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Legend
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Group 12, by modern IUPAC numbering, is a group of chemical elements in the periodic table. It includes zinc (Zn), cadmium (Cd) and mercury (Hg). The further inclusion of copernicium (Cn) in group 12 is supported by recent experiments on individual copernicium atoms. Group 12 is also known as the volatile metals, although this can also more generally refer to any metal (which need not be in group 12) that has high volatility, such as polonium or flerovium. Formerly this group was named IIB (pronounced as "group two B", as the "II" is a Roman numeral) by CAS and old IUPAC system.
The three group 12 elements that occur naturally are zinc, cadmium and mercury. They are all widely used in electric and electronic applications, as well as in various alloys. The first two members of the group share similar properties as they are solid metals under standard conditions. Mercury is the only metal that is a liquid at room temperature. While zinc is very important in the biochemistry of living organisms, cadmium and mercury are both highly toxic. As copernicium does not occur in nature, it has to be synthesized in the laboratory.
Like other groups of the periodic table, the members of group 12 show patterns in its electron configuration, especially the outermost shells, which result in trends in their chemical behavior:
Group 12 elements are all soft, diamagnetic, divalent metals. They have the lowest melting points among all transition metals. Zinc is bluish-white and lustrous, though most common commercial grades of the metal have a dull finish. Zinc is also referred to in nonscientific contexts as spelter. Cadmium is soft, malleable, ductile, and with a bluish-white color. Mercury is a liquid, heavy, silvery-white metal. It is the only common liquid metal at ordinary temperatures, and as compared to other metals, it is a poor conductor of heat, but a fair conductor of electricity.