Example 1 · difficulty 2/5
In a proposed Dobereiner triad, the atomic masses of the first and third elements are 6.9 u and 39.1 u. What atomic mass is expected approximately for the middle element?
- A. 20.0 u
- B. 23.0 u
- C. 32.0 u
- D. 46.0 u
2019 source guide · Chemistry
NEET 2019 Chemistry Periodic Properties Questions
Use this page to connect the official 2019 paper with current Chemistry practice. NeetVellum does not claim a chapter appeared in that paper until the official question and final key have been mapped.
What to master
periodic trends, effective nuclear charge and anomalous behaviour.
Original practice preview
These are current-syllabus NeetVellum questions, shown separately from historical-paper provenance.
Example 2 · difficulty 1/5
Which set is a recognised example of a Dobereiner triad?
- A. Li, Mg, K
- B. F, Cl, I
- C. Ca, Sr, Ba
- D. C, Si, Sn
Example 3 · difficulty 1/5
Why could Dobereiner's triads not serve as a general classification of all known elements?
- A. They used atomic numbers before atomic numbers were known
- B. They included only gaseous elements
- C. They denied all similarities among elements
- D. Only a limited number of elements could be grouped into satisfactory triads
The evidence-first practice loop
- 1. Verify provenanceOfficial paper and final key before accepting a PYQ label.
- 2. Attempt closed-bookExpose the concept or execution gap before rereading.
- 3. Repair and returnClassify the miss and re-practice after a delay.
Canonical chapter practice
Frequently asked questions
Are these official NEET 2019 Chemistry Periodic Properties PYQs?
No. The previews are original NeetVellum practice questions. A historical item receives a PYQ label only after its official paper and authoritative final answer key are attached. Use the official archive for the source paper.
How should I use the NEET 2019 paper?
Solve the official paper under its original timing, verify against the final key, classify every miss, and then use the linked current-syllabus practice bank to repair the exposed concept.