Ncert science solutions class 9 Solutions for Chapter 4 structure of the atom

Exercises in Chapter 4 structure of the atom Grade 9

Structure of the Atom - Exercise 4.1

Structure of the Atom - Exercise 4.2

Structure of the Atom - Exercise 4.3

Structure of the Atom - Exercise 4.4

Structure of the Atom - Exercise 4.5

Structure of the Atom - Exercise 4.6

Structure of the Atom - Exercise 4.7

Questions in Structure of the Atom - Exercise 4.1

What are the canal rays?

If an atom contains one electron and one proton, will it carry any charge or not?

Questions in Structure of the Atom - Exercise 4.2

Draw a sketch of Bohr’s model of an atom with three shells.

Questions in Structure of the Atom - Exercise 4.3

Write the distribution of electrons in Carbon and Sodium atoms.

If K and L shells of an atom are full, then what would be the total number of electrons in the atom?

Questions in Structure of the Atom - Exercise 4.4

How will you find the valency of chlorine, sulphur and magnesium?

Questions in Structure of the Atom - Exercise 4.5

With the help of given Table, find out the mass number of oxygen and sulphur atom.

Table: Composition of Atoms of the First Eighteen Elements with Electron Distribution in Various Shells.

Questions in Structure of the Atom - Exercise 4.6

For the symbol H, D and T, tabulate three subatomic particles found in each of them.

Write the electronic configuration of any one pair of isotopes and isobar.

Questions in Structure of the Atom - Exercise 4.7

What are the limitations of J.J.Thomson’s model of the atom?

Explain with examples

(i) Atomic number,

(ii) Mass number,

(iii) Isotopes and

(iv) Isobars.

Give any two uses of isotopes.

Na+ has completely filled K and L shells. Explain.

If bromine atom is available in the form of, say, two isotopes $_{35}Br^{79}$ (49.7%) and $_{35}Br^{81}$ (50.3%), calculate the average atomic mass of Bromine atom.

Which one of the following is a correct electronic configuration of Sodium?

(a) 2, 8

(b) 8, 2, 1

(d) 2, 8, 1

Complete the following table.

Atomic number	Mass number	Number of neutrons	Number of Protons	Number of electrons	Name of the atomic species
9	-	10	-	-	-
16	32	-	-	-	Sulphur
-	24	-	12	-	-
-	2	-	1	-	-
-	1	0	1	0	-

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Chapters in this book

Matter in Our Surroundings

Is Matter Around Us Pure

Atoms and Molecules

Structure of the Atom

The Fundamental Unit of Life

Tissues

Diversity in Living Organisms

Motion

Force and Laws of Motion

Gravitation

Work and Energy

Sound

Why Do We Fall ill

Natural Resources

Improvement in Food Resources