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ATOMIC THEORY -1

Total questions: 10

Worksheet time: 5mins

Name
Class
Date
1.

Who discovered electron

a)

Neils Bohr

b)

J J Thompson

c)

John Dalton

d)

Demicritus

2.

What is mass number of an atom

a)

protons + electrons

b)

protons alone

c)

protons + neutrons

d)

neutrons alone

3.

mass number is 38 and atomic number is 18.How many protons are there?

a)

20

b)

21

c)

19

d)

18

4.

Which is responsible for mass of an atom

a)

only protons

b)

only neutrons

c)

protons + neutrons

d)

protons + electrons

5.

Which of the following determines atomic number of an atom

a)

number of protons

b)

number of neutrons

c)

number of protons + number of electrons

d)

number of protons + number of neutrons

6.

An atom differs from an ion with respect to which of the following

a)

number of protons

b)

number of electrons

c)

mass number

d)

atomic number

7.

Bohr condition for stationary orbits

a)

mvpi = nh/2

b)

mvr 2 pi = nh

c)

mv/2 pi = nh

d)

mvnh = 2 pi

8.

Existence of nucleus was discovered by

a)

J J Thompson

b)

Rutherford

c)

Bohr

d)

Dalton

9.

Rutherford failed to explain

a)

existence of nucleus

b)

existence of electrons

c)

distribution of electrons

d)

space in the atom

10.

Bohrs model failed to explain

a)

hydrogen atom

b)

energy of electron

c)

selection of stationary orbits

d)

mathematical assumption to select stationary orbits