Question

1 . Describe the chemistry of the group 14 elements with reference to (i) decreasing
catenation, (ii) increased metallic behaviour on descending the group and (iii) the relative
stability of the +2 and +4 oxidation states.

2. Discuss with relevant examples how the stability of the +2 oxidation state varies across
the 1st row transition metals. Describe with relevant examples the general types of
ligands that can stabilise higher oxidation states in metal complexes.

3. Discuss in detail the spectroscopic techniques used to examine toxic metal concentration
in the human body and how these techniques are applied.

please answer all

Answer 1

Group 14 elements are C Si Ge Sn Pb.

1. catenation is the property of element to bond itself through covalent bond

The order of catenation property is:
C >> Si > Ge >> Sn > Pb.

Catenation is the property of non-metal having small size. As we move down group, size increases. Due to this bond trength decreases. hence bonding property of element decreases as a result catenation decreases

2. Metallic character is due to the fotrmation iof metal cation by loosing electrons, Metals has property to lose electrons in chemical reactions.

As we move down the group, there is less shielding of electrons by the nucleus or weaker nucleus attraction hence the tendency to remove electron increases.Thererfore metallic charcter increases.

3. Oxidation means loss of electrons .

Oxidation state +2 and +4

General electronic configuration of 14 the group is ns2np2 . That means 4 valence electrons.

by loosing 2 electrons the element is left with filled ns2 orbitals. We know half filled and fully filled orbitals provide extra stability. Thus +2 is stable oxidation state. (innert pair effect also work)

By loosing 4 electrons the element has lost all of its valence elctrons and achived stable noble gas configuration. This provide extra stability to the element in +4 oxidation state. Thus +4 is stable oxidation state.