Which of the following species has the highest number of unpaired electrons?

1. Fe²⁺

2. Fe³⁺

3. Co³⁺

4. Co²⁺

The atomc number of potassium is 19 & that of manganese is 25. Although the colour of MnO₄^- is dark violet yet the K⁺ is colourless.This is due to the fact that

(1) Mn is a transition element; while K⁺ is not

(2) [MnO₄]^- is negatively charged; while K⁺ has a positive charge.

(3) The effective atomic number of Mn in [MnO₄]^- is 26; while for K⁺ , the atomic number s 18

(4) The Mn in a high positive oxidation state allow charge transfer transitions.

Heating of Ag with dil. HNO₃ give

1. NO

2. NO₂

3. N₂O

4. N₂O₃

Zinc dissolve in an excess of NaOH because of the formation of:

1. ZnO

2. Zn(OH)₂

3. NaZn(OH)₃

4. Na₂ZnO₂

When excess of SnCl₂ is added to HgCl₂, the substance formed is

1. Hg₂Cl₂

2. Sn

3. Hg

4. Cl₂

The oxidation number is changed in which of the following case

1. SO₂ gas is passed into $C{r}_2{O}_7^{2-}/H^{+}$

2. Aqueous solution of $Cr{O}_4^{2-}$ is acidified

3. $Cr{O}_{2}C{l}_2$ is dissolved in NaOH

4. $C{r}_2{O}_7^{2-}$ solution is made alkaline

Which of the following elements form stable dinuclear ions

1. Zn

2. Cd

3. Hg

4. Fe

The correct electronic configuration of Ti(Z=22 atom) is

(1) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^2$

(2) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{2}4p^6$

(3) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^4$

(4) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^2$

The correct statement regarding colour of Zn²⁺, Ni²⁺and Cr³⁺among the following is:

The incorrect statement regarding the transition metals is: