Questions

Short answer type

1. Define the following terms

a. Stationary orbit

b. Valency

c. Valence shell

2. Draw the planetary model of an atom

3. Give the location of electrons, protons and neutrons in an atom.

4. Why did Rutherford use gold foil for his scattering experiment?

5. State the drawback of Rutherford’s model of atom?

 

Long answer type

1. Atom is electrically neutral though it contains charged particles in it. Why?

2. State the assumptions of Bohr’s theory.

3. What do you mean by stationary orbit? Which condition is satisfied by these orbits?

 

More Questions

4. How did Thomson discover electron in the atom?

5. Draw the labeled diagram for the following:

a. Rutherford’s scattering experiment

b. Different shells of atom with number of electrons in each

 

Give reasons for the following :

1. Helium atom does not combine with any other atom

2. The predicted valency of sodium is one

3. Rutherford’s atom failed

4. The second shell of an atom can accommodate 8 electrons

5. The mass atom is concentrated in its nucleus

 

State whether true or false :

1. The valency of oxygen is 6.

2. Mass of a neutron is just less than the mass of a proton

3. Thomson proposed that the nucleus of atom contains only nucleons

4. Cathode rays are negatively charged

 

Fill in the blanks :

1. Neutron was discovered by —

2. The ’N’ shell of an atom can accommodate maximum —electrons

3. The ’Christmas Pudding’ model of atom was proposed by —

4. The charge on the electron is — coulombs

5. Rutherford chose —foil for his experiment

 

Multiple choice questions :

1. —atom does not have neutron in its nucleus

a. sodium

b. chlorine

c. hydrogen

d. neon

2. The atomic number of chlorine is 17. The number of electrons in its valence shell is —

a. 5

b. 6

c. 7

d. 3

3. When a gas at reduced pressure is subjected to high voltage, rays coming out from negative electrode are called —

a. anode rays

b. cathode rays

c. x –rays

d. ν –rays

4. An element has electron configuration 2,6. The element is —

a. carbon

b. nitrogen

c. oxygen

d. fluorine

5. The outermost orbit of any atom can have maximum —electrons

a. 2

b. 8

c. 18

d. 32

 

Answer the following question

1. An atom of an element has 18 protons, 18 electrons and 22 neutrons.

a. What is the atomic number of the element?

b. Write the electron distribution in the orbits of the atom.

c. Name the element

 

More difficult questions :

1. An element has atomic number 118. It will require —shells to accommodate all the electrons.

a. 5

b. 6

c. 7

d. 8

2. In his α –particle scattering experiment, Rutherford chose gold foil because —

a. a foil of about 1000 atoms thickness can be prepared for gold.

b. gold is a heavy element with many protons and electrons. It has lot of empty space in the atom.

c. gold is a shining metal and reflects rays to a great extent

d. gold is a noble metal, it is not affected by atmospheric air or chemical reagents.

3. The number of nucleons (protons + neutrons) for some elements are given in brackets below. Which pair of elements has same number of neutrons? N (14), O (16), F(17), Ne(20)

a. N,O

b. O, F

c. F, Ne

4. Which of the following assumptions of Bohr’s theory stands as a correction to Rutherford’s model of atom?

a. there is a positively charged nucleus at the centre of the atom

b. electrons revolve around the nucleus without radiating energy

c. the number of electrons in orbits is equal to the number of protons.

d. the space between the two orbits is a forbidden area for the electrons

5. The atomic numbers of some elements are given in brackets below. Which pair of elements will show the same valency ? N (7), O(8), Si (14), P (15), Cl (17)

a. N,O

b. Si, P

c. P, Cl

d. N, P

 

Answers–1) c 2) a 3) b 4) b 5) d