Using the half-life formula:
\( t = \frac{\ln(N_0/N)}{\ln(2)} \times T_{1/2} \)
where \(N_0 = 10\), \(N = 2.5\), and \(T_{1/2} = 5730\) years.
Substituting the values:
\( t = \frac{\ln(10/2.5)}{\ln(2)} \times 5730 = 11460 \text{ years}. \)
| Group I | Group II |
| P) NaCl | 1) Coordination bond |
| Q) $H_2$ | 2) Polar covalent bond |
| R) $Pd-P$ bond in $Pd(PPh_3)_4 | 3) Covalent bond |
| S) $C-Cl$ bond in $CH_3Cl $ | 4) Ionic bond |

