Properties of Some Transition Metal Compounds

Experiment 7

Title: Properties of some transition metal compounds

Introduction:

Transition elements are elements that can form 1 or more stable ions that have incompletely filled electrons in the d-orbitals. Because they possess the properties of metals, the transition elements are also known as the transition metals. These elements are very hard, with high melting points and boiling points.

Moving from left to right across the periodic table, the five d orbitals become more filled. The d electrons are loosely bound, which contributes to the high electrical conductivity and malleability of the transition elements. The transition elements have low ionization energies. They exhibit a wide range of oxidation states or positively charged forms. The positive oxidation states allow transition elements to form many different ionic and partially ionic compounds. The formation of complexes causes the d orbitals to split into two energy sublevels, which enables many of the complexes to absorb specific frequencies of light. Thus, the complexes form characteristic coloured solutions and compounds. Complexation reactions sometimes enhance the relatively low solubility of some compounds.

The metal ions of the transition element are acidic in nature. This is due to deprotonation. The positive metal ion is complexed with 6 water molecules. However, the positive charge on these molecules attracts the electron on one of the hydroxide bond of the water molecule. This releases the proton (H+ ion). The proton will then be attracted to the lone pair of an oxygen atom in water molecule forming H3O+ ion. This results in an acidic solution.

Objectives:

1)To identify the properties of transition metals.

2) to identify the different colours of transition metal

3) to identify the different oxidation states of transition metal

Material and chemicals:

0.1 mol/L CrCl3 solution, 0.1 mol/L K2CrO4 solution, 0.1 mol/L MnSO4 solution, 0.01 mol/L KMnO4 solution, FeSO4...