Class 10 Science - Chapter Periodic Classification of Element NCERT Solutions | (a) Lithium, sodium, potassium are all m

(a)  What property do all elements in the same column of the Periodic Table as boron have in common?
(b)  What property do all elements in the same column of the Periodic Table as fluorine have in common?

The position of three elements A, B and C in the Periodic Table are shown below –

      Group 16          Group 17
            -                       -
            -                       A
            -                       -
            B                      C

(a) State whether A is a metal or non-metal.
(b) State whether C is more reactive or less reactive than A.
(c) Will C be larger or smaller in size than B?
(d) Which type of ion, cation or anion, will be formed by element A?

Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.

How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?

Which element has

(a) two shells, both of which are completely filled with electrons?
(b) the electronic configuration 2, 8, 2?
(c) a total of three shells, with four electrons in its valence shell?
(d) a total of two shells, with three electrons in its valence shell?
(e) twice as many electrons in its second shell as in its first shell?

How could the Modern Periodic Table remove various anomalies of Mendeléev’s Periodic Table?

Element X forms a chloride with the formula XCl₂, which is a solid with a high melting point. X would most likely be in the same group of the Periodic Table as

     (a) Na     (b) Mg     (c) AI     (d) Si

Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.

Use Mendeléev’s Periodic Table to predict the formulae for the oxides of the following elements:

    K,     C,      AI,      Si,      Ba.

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

What is a good source of energy?

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

What changes can you make in your habits to become more environment-friendly?

What is the difference between a reflex action and walking?

What is the importance of DNA copying in reproduction?

If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?

Why should a magnesium ribbon be cleared before burning in air?

Define the principal focus of a concave mirror.

You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

Describe the structure and functioning of nephrons.

Give two important uses of washing soda and baking soda.

A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains

  (a) NaCl          (b) HCl          (c) LiCl          (d) KCl

Why is variation beneficial to the species but not necessarily for the individual?

Choose the correct option.

A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each

       (a) two revolutions         (b) one revolution
       (c) half revolution           (d) one-fourth revolution

Name some devices in which electric motors are used.

Define the principal focus of a concave mirror.

Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics?

State two ways to prevent the rusting of iron.