Eduprobe
Question:
Following table shows the successive molar ionisation energy (kJ mol⁻¹) of five elements A to E.
| Element | Ionisation energy (kJ mol⁻¹) |
|---|---|
| 1st | 2nd |
| A | 2080 |
| B | 500 |
| C | 740 |
| D | 580 |
| E | 420 |
| Which two elements are most likely to be in the same group of the periodic table? |
C and D
B and E
D and E
B and D
Solution:
On comparing the second ionization energy of B and E, we see that they are exceptionally high. This suggests that these elements have only one electron in their outermost shell. After losing this electron, they achieve a stable noble gas configuration. Therefore, they are likely to be in the same group, which is the first group, i.e., alkali metals.