| A. | Unlike Ga that has a very high melting point, Cs has a very low melting point. |
| B. | On Pauling scale, the electronegativity values of N and Cl are not the same. |
| C. | \(Ar, K^+, Cl^-, Ca^{2+}\) and \(S^{2-}\) are all isoelectronic species. |
| D. | The correct order of the first ionization enthalpies of Na, Mg, Al, and Si is Si > Al > Mg > Na |
| E. | The atomic radius of Cs is greater than that of Li and Rb. |
| 1. | C and D only |
| 2. | A, C and E only |
| 3. | A, B and E only |
| 4. | C and E only |
| 1. | Si < C < O < N < F | 2. | O < F < N < C < Si |
| 3. | F < O < N < C < Si | 4. | Si < C < N < O < F |