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 Copper, Cu, Transition Metal. Between the metals of the new group, which is called after copper. Of the heavy metals already discussed, copper. Besides being used in the pure state, copper. Is also extensively employed for alloys. Brass has already been mentioned; others will be given later. Of the Sinai Peninsula were extensively worked by the Egyptians about the year 3700 b. Must have been known in Cyprus for many centuries previous to their production. Copper daggers found in Northern Italy .

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.

In its chemical relations mercury, or Hydrargyrum, is most nearly allied to copper, since it forms, like it, two elementary ions, a monovalent and a divalent, which in many respects also are similar to those of copper. With cadmium it shares the tendency to form slightly dissociated halogen compounds of the divalent series. Pneumatic trough for the investigation of gases at once led to the discovery of a series of hitherto unknown substances.

Element Nickel, Ni, Transition Metal. Unlike cobalt, which is not employed in the metallic state, metallic nickel is a material which is greatly used. It was formerly used only for alloys; thus German silver is an alloy of nickel with zinc and copper. Some decades ago, however, the difficulties caused by the high temperature of fusion of nickel. The electrical deposition of a metal depends on the fact that at the cathode of a circuit, the cations pass from the state of ions into the neutral state.

Element Palladium, Pd, Transition Metal. Was discovered by William Hyde Wollaston in 1803, also in raw platinum, in the part soluble in aqua regia. When Wollaston separated some quantity of the metal, he, without reporting about the discovery, distributed anonymous advertising about new metal named palladium. This element was named by Wollaston in 1804 after the asteroid Pallas, which was discovered by named by astronomer Heinrich Wilhelm Matthäus Olbers two years earlier.

Element Zinc, Zn, Transition Metal. From the metals of the iron group, to which it is in many respects similar, zinc. Differs in the fact that it cannot form any other stage of combination than that containing divalent ion. In this respect it forms an intermediate member between nickel, which has lost this property for the most part, and magnesium, in the case of which no trace of that property is present. Resist the influence of air and water fairly well.