Listed below are the locations of certain elements in groups and periods of the periodic table. Arrange these elements in the expected order of increasing first ionisation energy.
P: Element in the fourth period and group IVA
Q: Element in the third period and group VIA
R: Element in the sixth period and group IIIA
S: Element in the second period and group VIIIA
T: Element in the fourth period and group VIA

Options

A. `P lt Q lt R lt S lt T`
B. `T lt S lt R lt Q lt P`
C. `R lt P lt T lt Q lt S`
D. `S lt Q lt T lt P lt R`

Explanation

To arrange the elements P, Q, R, S, and T in the expected order of increasing first ionization energy, we will follow these steps:

### Step 1: Identify the Elements
- **P**: 4th period, Group IVA (Carbon group)
- **Q**: 3rd period, Group VIA (Chalcogens)
- **R**: 6th period, Group IIIA (Boron group)
- **S**: 2nd period, Group VIIIA (Noble gases)
- **T**: 4th period, Group VIA (Chalcogens)

### Step 2: Understand Ionization Energy Trends
- Ionization energy generally increases across a period (left to right) due to increasing nuclear charge and decreasing atomic radius.
- Ionization energy generally decreases down a group (top to bottom) due to increasing atomic size and shielding effect.

### Step 3: Analyze Each Element
1. **Element S (2nd period, Group VIIIA)**: Noble gases have high ionization energies due to their stable electron configuration.
2. **Element Q (3rd period, Group VIA)**: Chalcogens have relatively high ionization energies, but lower than noble gases.
3. **Element P (4th period, Group IVA)**: This element has a moderate ionization energy, higher than that of Group IIIA and lower than Group VIIIA.
4. **Element T (4th period, Group VIA)**: Similar to Q but in the same period, it will have a lower ionization energy than Q.
5. **Element R (6th period, Group IIIA)**: Being in a lower period, it will have the lowest ionization energy due to increased atomic size and shielding.

### Step 4: Arrange in Order of Increasing Ionization Energy
Based on the above analysis, we can arrange the elements in order of increasing first ionization energy:
- R (lowest)
- T
- P
- Q
- S (highest)

### Final Order
**R < T < P < Q < S**