d and f-block elements

Question 1

Elements of 3d Series

Answer 1

Scandium-Zinc

Question 2

Elements of 4d Series

Answer 2

Yttrium-Cadmium

Question 3

Elements of 5d Series

Answer 3

Lanthanum-Mercury

Question 4

Elements of 6d series

Answer 4

Actinium-Copernicium

Question 5

Which transition metal does not occur in nature?

Answer 5

Technitium

Question 6

Coinage metals

Answer 6

Cu,Ag, Au

Question 7

Physical Properties of transition metals

Answer 7

1. good conductors of heat and electricity
2. metallic lustre
3. strong
4. ductile

Question 10

Trend of atomic radii for d-block elements

Answer 10

Reason : e entering d orbitals shield the nuclear charge incompletely, thus the nuclear charge attracts all the electrons more strongly due to which contraction in size occurs.

1. decreases left to right, slightly increases towards the end
2. electrons entering d orbitals shield nucleae charge incompletely

nucleus attracts electrons more strongly, hence contraction in size

Question 11

Ionisation Enthalpy Trend for d-block

Answer 11

1. increases left to right, but no appreciable change
2. increase in IE is due to increase in nuclear charge
3. increase in nuclear charge is balanced by increase in screening effect.

Question 12

Oxidation States for Sc, Ti, V, Cr

Answer 12

• Sc: +3
• Ti:+2,+3,+4
• V:+2,+3,+4,+5
• Cr:+1,+2,+3,+4,+5,+6
• Mn:+2,+3,+4,+5,+6,+7

Question 13

Oxidation States for Mn, Fe, Co, Ni, Cu, Zn

Answer 13

• Fe:+2,+3,+4,+6
• Co:+2,+3,+4
• Ni:+2,+3,+4
• Cu:+1,+2
• Zn:+2

Question 14

What O.S does Mn show in acidic medium and alkaline medium?

Answer 14

• acidic : +2
• alkaline: +4

Question 15

What is the difference between O.S of d-block elements?

Answer 15

• unlike p block elements, where O.S differs by 2 units, here OS varies by 1unit for mixed oxides.

Question 16

3 examples of mixed oxides

Answer 16

• Mn3O4
• Fe3O4
• Co3O4

Question 17

Why do d-block elements show colour?

Answer 17

• metal ion has unpaired electrons
• when electron goes from lower energy orbital to higher energy orbital, if excitation energy lies in visible range then complimentary color is observed.

Question 18

Which O.S is stable for elements of 3d series?

Answer 18

• +3: Ti,V,Cr
• +2:rest of the elements
• Ni, Cu, Zn do not show +3 at all
  ***