NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1 Class 10 Science Class book solutions are available in PDF format for free download. These ncert book chapter wise questions and answers are very helpful for CBSE Board exam. CBSE recommends NCERT books and most of the questions in CBSE exam are asked from NCERT text books. Class 10 Science chapter wise NCERT solution for Science Book for all the chapters can be downloaded from our website and myCBSEguide mobile app for free.

NCERT solutions for Class 10 Science Periodic Classification of Elements Download as PDF

NCERT Class 10 Science Chapter wise Solutions

• 1 – Chemical Reactions and Equations
• 2 – Acids, Bases and Salts
• 3 – Metals and Non-metals
• 4 – Carbon and Its Compounds
• 5 – Periodic Classification of Elements
• 6 – Life Processes
• 7 – Control and Coordination
• 8 – How do Organisms Reproduce?
• 9 – Heredity and Evolution
• 10 – Light Reflection and Refraction
• 11 – Human Eye and Colourful World
• 12 – Electricity
• 13 – Magnetic Effects of Electric Current
• 14 – Sources of Energy
• 15 – Our Environment
• 16 – Management of Natural Resources

NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

1. Did Dobereiner’s triads also exist in the columns of Newland’s Octaves? Compare and find out?

Ans. Yes, following triads can be identified:

Li, Na, K

Be, Mg, Ca

The atomic mass of middle atom in the above triads is approximately equal to the average mass of elements on the left and right hand side.

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NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

2. What were the limitations of Dobereiner’s classification?

Ans. Dobereiner could identify only three triads from the elements known at that time. Hence, this classification of elements was not found to be useful.

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NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

3. What were the limitations of Newland’s law of octaves?

Ans. The limitations of Newlands’ Law of Octaves:

(a) it was found that Law of Octaves was applicable only upto calcium.

After calcium eighth element did not possess properties similar to that of first.

(b) Newlands’ assumed that only 56 elements existed in nature and no more elements would be discovered in future.

(c) To fit the element into his table, Newlands adjusted two elements in the same slot but also put some unlike elements under the same note.

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NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

1. Use Mendeleev’s Periodic Table to predict the formulae for the oxides of the following elements:

K, C, Al, Si, Ba

Ans. K₂O, CO₂, SiO₂, BaO

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2. Besides gallium, which other elements have since been discovered that were left by Mendeleev in his Periodic Table? (any two)

Ans. Scandium and Germanium.

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NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

3. What were the criteria used by Mendeleev in creating his Periodic table?

Ans. Mendeleev created his Periodic Table on the basis of their fundamental property the atomic mass and also on the similarities of chemical properties. Among chemical properties he concentrated on the compounds formed by elements with oxygen and hydrogen.

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4. Why do you think the noble gases are placed in separate group?

Ans. Noble gases are inert elements. Their properties are different from the all other elements. Therefore, the noble gases are placed in a separate group.

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NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

1. How could the Modern Periodic table remove various anomalies of Mendeleev’s Periodic Table?

Ans. Modern Periodic Table settled the placement of isotopes as isotopes have same atomic number.

Position of controversial position of hydrogen is also settled in modern periodic table.

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NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

2. Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice?

Ans. Calcium and Strontium would show chemical reactions similar to magnesium. They have the same number of electrons in the outermost shell.

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NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

3. Name:

(a) Three elements that have a single electron in their outermost shells.

(b) Two elements that have two electrons in their outermost shells.

(c) Three elements with filled outermost shells.

Ans. (a) Lithium, sodium and potassium have a single electron in their outermost shells.

(b) Magnesium and calcium have two electrons in their outermost shells.

(c) Helium, neon and argon have filled outermost shells.

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NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

4. (a) Lithium, sodium and potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?

(b) Helium is an un-reactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?

Ans. (a) Lithium, sodium and potassium have same number of electrons in the outermost shell.

(b) Helium and argon have completed outermost shell, 2 electrons in case of helium and 8 electrons in case of argon.

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5. In the Modern Periodic Table, which are the metals among the first ten elements?

Ans. Lithium and Beryllium are the metals among the first ten elements in the Modern Periodic Table.

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NCERT Solutions for Class 10 Science Periodic Classification of Elements Part 1

6. By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic?

Ga, Ge, As, Se, Be

Ans. Metallic character of an element increases down a group and decreases from left to right in period. On this basis Be is expected to have maximum metallic character.

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