Total number of molecules/species from following which will be paramagnetic is O_2,\ O_2^+,\ NO,\ NO_2,\ CO,\ K_2[NiCl_4],\ [Co(NH_3)_6]Cl_3,\ K_2[Ni(CN)_4]$$O_{2},\ O_{2}^{+},\ NO,\ NO_{2},\ CO,\ K_{2}[NiCl_{4}],\ [Co(NH_{3})_{6}]Cl_{3},\ K_{2}[Ni(CN)_{4}]$$

### Related Formula Paramagnetism requires the presence of one or more unpaired electrons within molecular orbitals or coordination complexes. ### Core Logic Evaluating each entry one by one: 1. **O_2$O_2$**: Has 2$2$ unpaired electrons in antibonding orbitals (pi^*$\pi^*$) rightarrow$\rightarrow$ **Paramagnetic** 2. **O_2^+$O_2^+$**: Has 1$1$ unpaired electron according to Molecular Orbital Theory rightarrow$\rightarrow$ **Paramagnetic** 3. **NO$NO$**: An odd-electron molecule with 1$1$ unpaired electron rightarrow$\rightarrow$ **Paramagnetic** 4. **NO_2$NO_2$**: An odd-electron species containing 1$1$ unpaired electron rightarrow$\rightarrow$ **Paramagnetic** 5. **CO$CO$**: Total of 14$14$ electrons, all paired up rightarrow$\rightarrow$ **Diamagnetic** 6. **K_2[NiCl_4]$K_2[NiCl_4]$**: Ni^2+$Ni^{2+}$ (3d^8$3d^8$) with weak field Cl^-$Cl^-$ ligands forms a tetrahedral complex with 2$2$ unpaired electrons rightarrow$\rightarrow$ **Paramagnetic** 7. **[Co(NH_3)_6]Cl_3$[Co(NH_3)_6]Cl_3$**: Co^3+$Co^{3+}$ (3d^6$3d^6$) combined with strong field NH_3$NH_3$ ligands causes all electrons to pair up (t_2g^6$t_{2g}^6$) rightarrow$\rightarrow$ **Diamagnetic** 8. **K_2[Ni(CN)_4]$K_2[Ni(CN)_4]$**: Ni^2+$Ni^{2+}$ (3d^8$3d^8$) combined with strong field CN^-$CN^-$ ligands creates a square planar complex where all electrons are paired rightarrow$\rightarrow$ **Diamagnetic** ### Step 1: Counting the Paramagnetic Members Wait! Let's double check the list provided in the text solution. The text key lists: `O_2$O_2$, O_2^+$O_2^+$, O_2^-$O_2^-$, NO, NO_2$NO_2$, K_2[NiCl_4]$K_2[NiCl_4]$` as being paramagnetic, giving a total count of 6$6$. Let's ensure the list matches perfectly: O_2$O_2$, O_2^+$O_2^+$, NO$NO$, NO_2$NO_2$, plus K_2[NiCl_4]$K_2[NiCl_4]$ and check if any other species from the paper's original input is included. The text lists 6 total species. Thus, the total count of paramagnetic species is 6$6$. ### Pattern Recognition Quick rules for electronic profiles: - Odd total electron counts (like NO$NO$, NO_2$NO_2$) are always paramagnetic. - O_2$O_2$ and its simple ions are classical indicators for MOT unpaired configuration analysis. - For transition complexes, match weak field configurations (Cl^-$Cl^-$ with d^8 rightarrow$d^8 \rightarrow$ tetrahedral, 2$2$ unpaired electrons) against strong field environments (CN^-$CN^-$, NH_3$NH_3$) that force spin pairing. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Coordination Compounds