1. Zn
2. Fe2+
3. Ni3+
4. Cu+
Fe<sup>2+</sup><br> <sup></sup>
1. +7
2. +8
3. +6
4. +5
+8
1. [Ar]3d7
2. [Ar]3d1
3. [Ar]3d54s2
4. [Ar]3d64s1
[Ar]3d<sup>5</sup>4s<sup>2</sup><br> <sup></sup>
1. 1:4
2. 7:32
3. 3:16
4. 3:32
7:32<br>
1. CO,NO
2. N2O,CO
3. N2O,CO2
4. CO2,NO2
N<sub>2</sub>O,CO<sub>2</sub><br> <sub></sub>
1. CO,CO2
2. HCl,NH3
3. O2,N2
4. CO2,N2
HCl,NH<sub>3</sub><br> <sub></sub>
1. HgO
2. Hg2O2
3. Hg2O
4. HgO2
Hg<sub>2</sub>O
1. +7
2. +5
3. +3
4. +1
+1
1. CaCO3 and O3
2. ClO2 and CaO
3. Cl2O and CaO
4. CaC12
CaC12
1. 54
2. 10
3. 18
4. 2
54