Which of the following group of transition metals is called coinage metals? (RPMT 2008)

The transition metals which are extensively used in the making of ‘coin’ are called coinage metals. In the historic period copper Cu , silver Ag and gold Au were used to make coins. This is usually augmented with tin. Thus, (a) is the correct option. 9. Out of and (Z of Ti = 22, Co = 27, Cu = 29, Ni = 28), the colourless species are (CBSE AIPMT, AMU 2009) (a) 2 3 6 6 TiF and CoF (b) 2 2 2 4 Cu Cl and NiCl (c) 2 6 2 2 TiF and Cu Cl (d) 3 2 6 4 CoF and NiCl In 2 6 TiF , titanium is in the +4 oxidation state. It has an empty d-orbital 0 0 3d 4s . So