(a) The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev. List one advantage and one limitation of all the three attempts. (b) Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass. (c) State Modern periodic law.
(a) The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev. List one advantage and one limitation of all the three attempts. (b) Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass. (c) State Modern periodic law.
(a) (i) Dobereiner’s Triads: Advantage - It shows that elements with similar properties occur at regular intervals when elements are arranged in order of their atomic masses. Limitation - It failed to arrange all the known elements in the form of triads. (ii) Newland’s Law of Octaves: Advantage - It shows that elements with similar properties occur at regular intervals when elements are arranged in order of their atomic masses. Limitation - It failed to arrange all the known elements in the form of octaves. (iii) Mendeleev’s Periodic Table: Advantage - It could accommodate all the known elements in the periodic table. Limitation - It failed to explain the position of isotopes and isobars in the periodic table. (b) Henry Moseley (c) Elements with similar properties recur at regular intervals when elements are arranged in order of their increasing atomic numbers.
Marking Scheme
- 1None
Hint
The student should refer to the chapter on the Modern periodic table and the early attempts of Dobereiner, Newland, and Mendeleev to classify elements.
Quick Oral Answer
The student should be able to explain the advantages and limitations of each attempt and name the scientist who first showed that atomic number of an element is a more fundamental property than its atomic mass.
Analysis & Explanation
This question requires the student to analyze the early attempts of Dobereiner, Newland, and Mendeleev to classify elements and list one advantage and one limitation of each attempt. The student is also required to name the scientist who first showed that atomic number of an element is a more fundamental property than its atomic mass and state the Modern periodic law.
Common Mistakes
- 1The student may confuse the advantages and limitations of each attempt.
- 2The student may not be able to name the scientist who first showed that atomic number of an element is a more fundamental property than its atomic mass.
Interesting Facts
The Modern periodic table is a tabular arrangement of elements in order of their increasing atomic numbers.
The elements with similar properties recur at regular intervals when elements are arranged in order of their increasing atomic numbers.
Spotted a mistake or something unclear?
Tell us — we fix reported answers fast.
Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2018?
This question carries 5 marks in the CBSE Class 10 Science 2018 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Metals and Non-metals" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Metals and Non-metals" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2018 paper?
This is a Long Answer question from Section A in the CBSE Class 10 Science 2018 paper.