please... help with transition metals!!?

Question

hi, ive got 3 questions and would appreciate anyone answering...
1)how do the electron configurations of the different transition metals explain their location in the periodic table?

2) why do transition metals form complex compounds?

3)what property of transition metals makes some of them able to act as effective catalysts?

thanks to anyone who can help in advance... :)

thanks gervald..., but how does the fact that they can have several oxidation states make them effective catalysts?

Answer 1

1) d electrons are the most important feature of the transition elements. They are placed in the groups with group numbers equal to that of nd + (n+1)s electrons. For example scandium has 1 3d electron and 2 4s electrons. So it falls in the Group 3 of the periodic table.

2)These complexes have variable valencies due to the change in the orbitals by electrons from s to d. They have ions that have a very large charge/mass ratios. So, the highly positive ions attract the ligands. These ligands donate their lone pairs to the atoms. These are placed in the d orbitals.

3) Variable valencies. The atoms of these elements act as electron acceptors first and then donate the electrons to the reactants. This bypass route drastically reduces the activation energy of the reaction and so we can use them as catalysts.

Answer 2

1. d-orbitals (inner levels) filling up, hence they are in the d-block.
2. Empty inner orbitals mean that ligands can donate electrons into them to form complexes.
3. Low rise in ionisation erergies means that several oxidation states (valencies) are possible, and this makes them good catalysts.

Answer 3

maximum transition metals have a shielding oxide layer and that they require greater advantageous ionisation energies, as much as two or 3 electrons which could be bumped off on an analogous time as alkali metals purely a million to form cations. there are various potential issues from an energetics attitude.