Element Cadmium, Cd, Transition Metal. 1124; the formula of the element in the vaporous state is therefore Cd. Forms only one elementary ion, divalent cadmion, Cd. The metal dissolves, although very slowly, in aqueous acids with formation of this ion. Cadmion is colourless, and acts as a rather virulent poison on the lower and higher organisms. Its heat of formation from the metal is 77 kj. Is soluble in excess of ammonia. The solution contains complex cadmium-ammonia ions, Cd. Of the salts the sulphate .

Element Gold, Au, Transition Metal. May have been the first known metal used for ornamentation since Neolithic age, 5000 - 4000 years BC. In Egypt, Mesopotamia, India, China and other ancient countries golden ornamentation. Had been used since 3-2 millennia BC. Alchemists called it the king of metals. Is a trace element; its abundance is 4.

Element Indium, In, Poor Metal. He came to conclusion that his atomic weight should be approximately 114, and its capacity to form alums means that this element belongs to Aluminium subgroup. May embed into their crystal grids.

On account of its remarkable properties and of its occurrence in the metallic state, silver. In the pure state silver is a white tenacious metal, which can be readily drawn into wire, and made into very thin sheets by rolling or hammering. For use it is alloyed with 10 per cent of copper in order to make it harder. It conducts heat and electricity very well, and occupies, in this respect, the first place among the metals. Is also found in native form.