The period four transition metals includes the elements Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni) and Copper (Cu). By the IUPAC definition of transition elements Zinc (Zn) is not included yet it is very often regarded as one.
The period five transition metals include the elements Yttrium (Y), Zirconium (Zr), Niobium (Nb), Molybdenum (Mo), Technetium (Tc), Ruthenium (Ru), Rhodium (Rh), Palladium (Pd) and Silver (Ag). Like Zinc, Cadmium (Cd) is often regarded as a transition metal but is not one under the IUPAC definition.
The period six transition metals include the elements Lanthanum (La), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt), Gold (Au) and Mercury (Hg). Mercury has only very recently been considered a transition metal by IUPAC with the discovery of compounds which allow it to meet their definition.
The period seven transition metals include the elements Actinium (Ac), Rutherfordium (Rf), Dubnium (Db), Seaborgium (Sg), Bohrium (Bh), Hassium (Hs), Meitnerium (Mt), Darmstadtium (Ds), Roentgenium (Rg) and Copernicium (Cn). Copernicium is an unstable synthetic compound but despite being in group 12 it is expected to have properties that make it a transition metal by the IUPAC definition.