co-ordination compound and D block elements

Co-ordination Compounds
Coordination compound may be defined as a compound that results from the combination of apparently saturated molecules of different species and retain its identity in the solids as well as in dissolved state.
The formation of a coordination compound involves two components.
1. An acceptor : Which can accept a pair of electrons from the donor atom. The acceptor is usually a metal with vaccant orbitals available to accept a pair of electrons from one or more neutral molecules or anions.
In [Fe(CN)6]4–, Fe++ ion is an acceptor, which is also called as central metal ion, which acts as Lewis acid.
2. A donor : An atom or a molecule which can donate a pair of electrons is a donor. Such donor atoms or molecules are electron rich and are called ligands, which acts as a Lewis base.
Ligands may be neutral (NH3, H2O, C6H5N) or negatively charged species (:CN–,Cl–, Br–).Ligand is said to be unidentate if it has only one pair of electrons that it can donate e.g. Cl–, Br–, H2O etc.

IUPAC Nomenclature of complex compounds 

In order to name these compounds certain rules have been suggested by IUPAC.

1. The positive part of a coordination compound is named first and is followed by the negative part.

2. The ligands are named first followed by the central metal. The prefixes di- tri-, tetra- etc, are used to indicate the number of each kind of ligand present. The prefixes bis (two ligands) tris (three ligands) etc. are used when the polydentate ligands surround the central atom.

3. The ligands are named in alphabetical order. Names of the anionic ligands end in O, those of cationic in ium. Neutral ligands have their regular names except that H2O is named aqua; NH3 ammine; NO nitrosyl; and CO carbonyl.

4. The oxidation state of the central metal is indicated in roman numbers in a bracket.

5. When a complex species has negative charge, the name of the central metal ends in –ate. For some elements, the  name of ion is based on the latin name of the metal (For example, argentate for silver).

Ligand is said to be unidentate if it has only one pair of electrons that it can donate e.g. Cl–, Br–, H2O etc.

question on cooridanate compounds

1. Which one is/are flexidentate ligand

(1) Cl– (2) Br–

(3) both (1) and (2) (4)

2. The IUPAC name of Na[Co(CO)4] is 

(1) sodium tetracarbonylcobaltate (–1)

(2) sodium tetracarbonylcobaltate (+1)

(3) tetracarbonylcobaltate (–1) sodium

(4) sodiumtetracarbonylcobaltate (0)

3. Oxidation state of Metal is zero in metal complex

(1) [Cu(NH3)4]SO4

(2) [Pt(NH3)2Cl2]

(3) [Ni(CO)4]

(4) K3[Fe(CN)6]

4. The type of magnetism exhibited by [Mn(H2O)6]2+ ion is

(1) Paramagnetism

(2) Diamagnetism

(3) Both (1) and (2)

(4) None of these

5. Highest molar conductivity is exhibited by :

(1) [Co(NH3)6]Cl3 (2) [Co(NH3)4Cl2]Cl

(3) [Co(NH3)5Cl]Cl2 (4) [Co(NH3)3Cl3]

6. The coordination number and oxidation number of M in the complex, [M(NH3)5SO4]Cl are

(1) 10, 3 (2) 6, 4

(3) 2, 6 (4) 6, 3

7. The IUPAC name of Ni(CO)4 is

(1) tetracarbonyl nickelate (0)

(2) tetracarbonyl nickelate (II)

(3) tetracarbonyl nickel (0)

(4) tetracarbonyl nickel (II)

8. Which one of the following does not give a white precipitate with silver nitrate solution ?

(1) [Co(NH3)6]Cl3 (2) [Co(NH3)5Cl]Cl2

(3) [Co(NH3)4Cl2]Cl2 (4) [Co(NH3)3Cl3]

9. Theoretically, the number of geometrical isomers expected for octahedral complex, [Mabcdef] is

(1) 0 (2) 15

(3) 12 (4) 30

10. The effective atomic number of cobalt in the complex [Co(NH3)6]3+ is

(1) 36 (2) 33

(3) 24 (4) 30

11. The oxidation number of Pt in [Pt (C2H4) Cl3]– is

(1) +1 (2) +2

(3) +3 (4) +4

12. [Co(NH3)5 NO2]Cl2 and [Co(NH3)5(ONO)]Cl2 are related to each other as

(1) geometrical isomers

(2) linkage isomers

(3) co-ordination isomers

(4) ionisation isomers

13. The number of geometrical isomers of [Co(NH3)3(NO2)3]are

(1) 2 (2) 3

(3) 4 (4) nil

14. IUPAC name of complex, K3 [Al (C2O4)3] is

(1) potassium alumino oxalate

(2) potassium trioxalatoaluminate (III)

(3) potassium aluminium (III) oxalate

(4) potassium trixalatoaluminate (VI)

15. Which of the following is a hexadentate ligand?

(1) Acetylacetonato

(2) 8-Hydroxy quinolinato

(3) Ethylenediamine tetraacetato

CBSE chemistry IX atomic structure

1.         What is an orbit, shell or energy level?  

2.         What is the maximum capacity of outermost shell of an atom?

3.         How does a proton differ from an electron?

4.         Name the particles which actually determine the mass of an atom.

5.         What are the symbols used to represent different orbits? Arrange them in order of energy?

6.         What are isobars? Give one example.

7.         Give any three important applications of isotopes.

8.         State the number of electrons present in the outermost shell of the atoms of the following elements:

            (i)    Neon                    (ii)    Chlorine

9.         From the symbol , state:

            (i)     Mass number of phosphorus,

            (ii)    Atomic number of phosphorus, and

            (iii)   Electron configuration of phosphorus.   

10.       The atomic number of an element X is 16.

            (a)   Write down the electronic configuration of X.

            (b)   What will be the valency of X?

11.       Natural chlorine contains chlorine in the form of the isotope ³⁵Cl (75.5%) and ³⁷Cl (24.5%). Calculate the average atomic mass of natural chlorine.

12.       (a)   Which fundamental particle is equal in number in Mg²⁺ and Al³⁺ ions?

            (b)   Atomic numbers of nitrogen and oxygen are 7 and 8, respectively. Calculate the total number of electrons in nitrate (NO₃^–) ion.

13.       The nuclear composition of two atomic species X and Y is as follows:

            X: 17 protons; 18 neutrons

            Y: 17 protons; 20 neutrons

            What are their (i) atomic numbers (ii) mass numbers? What is the relation between these two atomic species? Name the element or elements which they represent.

14.       What valencies will be shown by the elements A, B, C, D and E having atomic numbers 2, 4, 8, 10 and 13 respectively?   

15.       (a)   An element has an atomic number 12 and an atomic mass number 26. Draw a diagram showing the distribution of electron in the orbits and the nuclear composition of the neutral atom of the element. What is the valency of the element and why is it so?

            (b)   Explain the structures of the following atoms giving diagrams:

                     and

16.       (a)   What was the drawback of Rutherford’s model of atom?

            (b)   Describe Rutherford’s a-ray scattering experiment and mention the observations derived from it. Cite one defect of Rutherford’s model of the atom.