Question

ANSWER ALL QUESTIONS PLEASE

1.   What are the characteristic electron configurations of transition metals?

      

2.   What is the general trend in atomic size across a transition metal series?

      

3.   Which electrons, 3d or 4s, have the lowest ionization energies in a transition metal?

      

4.   What is the general trend of the reducing strength across a transition metal series?

      

5.   Why do transition metals have similar chemical properties?

      

6.   Name four transition metals that are essential to the biological system.

1.      Write the electron configuration of the following elements using appropriate noble gas symbol to represent inner-shell electrons. Draw the orbital “box” diagram for the valence-shell electrons for these elements. Identify a diamagnetic element, the least paramagnetic element, and the most paramagnetic element. (Note: for transition metals, valence electrons include those in (n-1)d subshell.)

         

         (a) Sc (Z = 21)

         (b) Ti (Z = 22)

(c) Cr (Z = 24):

         (d) Mn (Z = 25):

         (e) Cu (Z = 29):

2.      Write the electron configuration and draw the orbital “box” diagram for the valence-shell electrons in the following ions using appropriate noble gas symbols for the inner-shells. Identify the ion that is diamagnetic, least paramagnetic, and the most paramagnetic ion.

         (a) Cr³⁺:

         (b) Mn²⁺:

         (c) Fe²⁺:

         (d) Fe³⁺:

         (e) Co²⁺:

         (f) Co³⁺:

         (g) Ni²⁺:

         (h) Cu⁺:

         (i) Cu²⁺

         (d) Zn²⁺

Model: Coordination Compounds

Coordination Compound	Complex Ion	Ligands	Counter Ion	Coordination Number	Oxidation State
[Co(H2O)6]Cl3	[Co(H2O)6]3+	H2O	Cl-	6	+3
K3[Fe(CN)6]	[Fe(CN)6]3-	CN-	K+	6	+3
[Cu(NH3)4]SO4	[Cu(NH3)4]-	NH3	SO42-	4	+2

3.   Name the following coordination compounds using systematic nomenclature.

1. [Co(H₂O)₆]Cl₂:

2. [Cr(NH₃)₆](NO₃)₃:

3. K₄[Fe(CN)₆]:

4. Na[Au(CN)₄]:

5. [Co(H₂O)₂(en)₂]Cl₃:

4.   Write the formula for the following coordination compounds:

1. Hexaamminecobalt(III) chloride =  

2. Diaquabis(ethylenediamine)chromium(III) nitrate =  

3. Potassium tetracyanozincate(II) =  

4. Sodium hexafluorocobaltate(III) =  

Answer 1

1. The orbitals present in the 3d and 4s subshells of the transition metals are of similar energy. In transition metals, the 4s subshell is having lower energy than the 3d subshell but In the transition metal ions of charge ≥ +2, 3d is of lower energy than 4s. In transition metal ions of charge ≥ +2, all valence electrons are present in the d-subshell.

2. In the transition metal elements, the number of electrons is increasing across a period but in a particular way. These number of electrons increases going across a period and resulted as a more pull of these electrons towards the nucleus. Thus the size of the metal is decreased across a period in a metals series.

3. The 4s electrons will be lost first and followed its 3d electrons. It is because the formation of the ions is clearly unsatisfactory. The 4s orbitals have lower energy than the 3d, and so the 4s orbitals are filled first and these electrons will be released early in comparison with the inner core electrons.

4. A good reducing agent that which is able to donate its electrons and themselves get oxidized during this process. Transition metals are not electron rich nor show electropositive character, therefore they are regarded as weak reducing agents. The reducing strength across a transition metal series is reduced due to an increase in the effective nuclear charge.

5. Generally, the elements in the same 'group' have similar chemical properties. It is because they have the same number of valence electrons in its outer electronic shell.