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Worksheets

Atoms and Molecules

Total questions: 20

Worksheet time: 8mins

Name
Class
Date
1.

Which of the following statements is not true about an atom?

a)

Atoms are always neutral in nature

b)

Atoms are not able to exist independently

c)

Atoms are the basic units from which molecules and ions are formed

d)

Atoms aggregate in large numbers to form the matter that we can see, feel or touch

2.

The chemical symbol for nitrogen gas is

a)

ni

b)

N2

c)

N

d)

NI

3.

The chemical symbol for sodium is

a)

so

b)

SO

c)

Na

d)

NA

4.

Which of the following has maximum number of atoms?

a)

18g of H2O

b)

18g of O2

c)

18g of CO2

d)

18g of CH4

5.

A change in the physical state can be brought about

a)

only when energy is given to the system

b)

only when energy is taken out from the system

c)

when energy is either given to or taken out from the system

d)

without any energy change

6.

molecular formula of copper and bromine is

a)

CuBr2

b)

CUBR

c)

Cu2Br

d)

CuBr

7.

Atomic number of oxygen is

a)

4

b)

6

c)

8

d)

12

8.

valency of helium is

a)

0

b)

3

c)

2

d)

1

9.

chemical formula of aluminium and hydrogen is

a)

aLoH

b)

Al(OH)3

c)

AL(OH)2

d)

AloH

10.

The molecular formula of potassium nitrate is ________.

a)

KNO

b)

KON

c)

KNO3

d)

KNO2

11.

Molecular mass is defined as the:

a)

Mass of one molecule of any substance compared with the mass of one atom of C – 12

b)

Mass of one atom compared with the mass of one atom of hydrogen

c)

Mass of one atom compared with the mass of one molecule

d)

none of these

12.

Atomic mass of sodium is

a)

13

b)

23

c)

21

d)

19

13.

Which of the following represents a correct chemical formula?

a)

BiPO4

b)

NaSO4

c)

NaS

d)

CaCl

14.

to create a chemical formal you need to know

a)

the atomic mass of an element

b)

the mass of an element

c)

valency of an element

d)

all of these

15.

atomic number of hydrogen is

a)

5

b)

7

c)

3

d)

1

16.

who presented the atomic theory

a)

Albert Einstein

b)

John Dalton

c)

Robert Hooke

d)

Marie Curie

17.

what is the symbol of silicon

a)

S

b)

Si

c)

SL

d)

Sc

18.

Atomicity of phosphorus namaste is

a)

monoatomic

b)

Diatomic

c)

poly atomic

d)

tetra atomic

19.

atomic radius is measured in

a)

nanometers

b)

kilometers

c)

meters

d)

centimeters

20.

which of the following is a noble gas

a)

helium

b)

oxygen

c)

aluminium

d)

hydrogen