ECAT Chemistry — Periodic Table and Periodicity
Periodic Table and Periodicity is part of the Chemistry section of the UET ECAT (30 of the 100 MCQs). It breaks into 1 subtopic, and we hold 20 ECAT-pattern practice MCQs on it, each with a written explanation. Tap a subtopic below to practise just that.
Subtopics (1)
How Periodic Table and Periodicity is tested
Across the 7 ECAT past papers on ParhaiKrlo, Periodic Table and Periodicity accounts for 7 questions. It appears in 6 of them, about 1.2 questions a paper. The heaviest was ECAT Past Paper 03, with 2 questions, and the most recent is ECAT Past Paper 07, with 1.
| Paper | Questions |
|---|---|
| ECAT Past Paper 07 | 1 |
| ECAT Past Paper 06 | 1 |
| ECAT Past Paper 05 | 1 |
| ECAT Past Paper 04 | 1 |
| ECAT Past Paper 03 | 2 |
| ECAT Past Paper 01 | 1 |
Periodic Table and Periodicity MCQs from the ECAT past papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · ECAT Past Paper 07 · Periodic Table and Periodicity
When an electron is added to O⁻, the energy change is expressed as:
- A.Electron affinity
- B.Energy release
- C.Energy absorption
- D.Both options A and C are correct
Show answer
Answer: D. Both options A and C are correct — The second electron affinity of oxygen is positive: energy must be absorbed to add an electron to the negative O⁻ ion.
- Q2 · ECAT Past Paper 06 · Periodic Table and Periodicity
The periodic table gives a basic framework to study the periodic behaviour of the physical and chemical properties of:
- A.Elements only
- B.Compounds only
- C.Elements and their compounds
- D.Elements and their inorganic compounds only
Show answer
Answer: C. Elements and their compounds — The periodic table organises elements, and the trends extend to their compounds (oxides, hydrides, halides…).
- Q3 · ECAT Past Paper 05 · Periodic Table and Periodicity
Ionization energy does NOT increase:
- A.With smaller atomic radius
- B.With increasing nuclear charge in a period
- C.With an increase in the number of electronic shells
- D.None of these
Show answer
Answer: C. With an increase in the number of electronic shells — More shells put the outer electron farther out and more shielded, so ionization energy decreases down a group.