Which of the following exhibits only a +3 oxidation state?
1. | Th | 2. | Ac |
3. | Pa | 4. | U |
Four successive members of the first series of the transition metals are listed below. For which one of them does the standard potential value have a positive sign?
1. Ni (Z = 28)
2. Cu (Z = 29)
3. Fe (Z = 26)
4. Co (Z = 27)
Lanthanoid's most common oxidation state is:
1. 2
2. 5
3. 3
4. 4
Which one of the following does not correctly represent the correct order of the property indicated against it?
1. | Ti3+< V3+< Cr3+< Mn3+: increasing magnetic moment |
2. | Ti < V < Cr < Mn : increasing melting point |
3. | Ti < V < Mn < Cr : increasing 2nd ionization enthalpy |
4. | Ti < V < Cr < Mn : increasing number of oxidation states |
The catalytic activity of transition metals and their compounds is ascribed mainly to:
1. their unfilled d-orbitals
2. their ability to adopt variable oxidation states
3. their chemical reactivity
4. their magnetic behaviour
The aqueous solution containing which one of the following ions will be colourless:
1. Fe2+
2. Mn2+
3. Ti3+
4. Sc3+
[Atomic number : Sc = 21, Fe = 26, Ti = 24, Mn = 25]
Four successive members of the first-row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionization enthalpy:
1. Vanadium (Z = 23)
2. Manganese (Z = 25)
3. Chromium (Z = 24)
4. Iron (Z = 26)
Colourless ion among the following is:
1. | Cr+4 | 2. | Sc+3 |
3. | Ti+3 | 4. | V+3 |
An element among the following that exhibits the maximum oxidation state is:
1. Cr
2. Mn
3. Fe
4. V
The main reason for a larger number of oxidation states exhibited by the actinoids than the corresponding lanthanoids is:
1. | Larger atomic size of actinoids than the lanthanoids |
2. | More energy difference between 5f and 6d orbitals than between 4f and 5d orbitals |
3. | Lesser energy difference between 5f and 6d orbitals than between 4f and 5d orbitals |
4. | Greater reactive nature of the actinoids than the lanthanoids |