3
MCQ (Single Correct Answer)
Metallic radii of some transition elements are given below. Which of these elements will have highest density?
| Element | Fe | Co | Ni | Cu |
|---|---|---|---|---|
| Metallic radii/pm | 126 | 125 | 125 | 128 |
A
Fe
B
Ni
C
Co
D
Cu
4
MCQ (Single Correct Answer)
Generally, transition elements form coloured salts due to the presence of unpaired electrons. Which of the following compounds will be coloured in solid state?
A
$\mathrm{Ag}_2 \mathrm{SO}_4$
B
$\mathrm{CuF}_2$
C
$\mathrm{ZnF}_2$
D
$\mathrm{Cu}_2 \mathrm{Cl}_2$
5
MCQ (Single Correct Answer)
On addition of small amount of $\mathrm{KMnO}_4$ to concentrated $\mathrm{H}_2 \mathrm{SO}_4$, a green oily compound is obtained which is highly explosive in nature. Identify the compound from the following.
A
$\mathrm{Mn}_2 \mathrm{O}_7$
B
$\mathrm{MnO}_2$
C
$\mathrm{MnSO}_4$
D
$\mathrm{Mn}_2 \mathrm{O}_3$
6
MCQ (Single Correct Answer)
The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.
A
$3 d^7$
B
$3 d^5$
C
$3 d^8$
D
$3 d^2$
7
MCQ (Single Correct Answer)
Which of the following oxidation state is common for all lanthanoids?
A
+2
B
+3
C
+4
D
+5