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Worksheets

Counting Atoms and Molecules

Total questions: 33

Worksheet time: 17mins

Name
Class
Date
1.
How many Hydrogen are in 4H2O?
a)
6
b)
8
c)
2
d)
4
2.
How many Magnesium are in 10MgCl2?
a)
10
b)
5
c)
20
3.
How many O's are in Al₂(SO₄)₃
a)
4
b)
12
c)
7
d)
24
4.
Number of H in 3(NH₄)₂CrO₄
a)
4
b)
2
c)
8
d)
24
5.
How many atoms are there TOTAL in:
H2SO4
a)
6
b)
5
c)
7
d)
3
6.
How many elements are in C6H12O6?
a)
1
b)
2
c)
3
d)
4
7.

How many different elements are present in H2COCH2

a)

5

b)

4

c)

3

d)

2

8.

The ______ are numbers found on the lower right-hand side of an element symbol.

a)

Coefficient

b)

Exponent

c)

Multiplier

d)

Subscript

9.

Coefficients in chemical formulas...

a)

Multiply just the first atom

b)

Add to the subscripts at the end of the molecule

c)

Multiply elements without subscripts

d)

Multiply EVERYTHING!

10.

4CF2Cl2

a)

C = 4, F = 4, Cl = 2

b)

C = 1, F = 8, Cl = 8

c)

C = 4, F = 8, Cl = 8

d)

C = 1, F = 4, Cl = 8

11.

C3H5(NO3)3

a)

C = 3, H = 5, N = 3, O = 9

b)

C = 3, H = 5, N = 1, O = 9

c)

C = 9, H = 15, N = 3, O = 9

d)

C = 9, H = 15, N = 1, O = 3

12.

H2SO4

a)

H = 2, S = 4, O = 4

b)

H = 2, S = 1, O = 4

c)

H = 8, S = 4, O = 4

d)

H = 2, SO = 4

13.

How many different elements are present in this molecule?

3 NH4C2H3O2

a)

15

b)

36

c)

5

d)

4

14.

A ______ is a number written in front of a chemical formula.

a)

Coefficient

b)

Subscript

c)

Exponent

d)

Coordinator

15.

The smallest piece of an element:

a)

quark

b)

electron

c)

shell

d)

atom

16.

The cloud-like space that electrons travel around:

a)

nucleus

b)

shell

c)

neutrons

d)

Oort cloud

17.

Protons and neutrons are found in the center of the atom called the:

a)

nucleus

b)

neutron

c)

shell

d)

cell

18.

The subatomic particles are called:

a)

protons, nucleus and electrons

b)

protons, electrons and neutrons

c)

protons, positives and negatives

d)

cloud, shell and quarks

19.

Electrons have a _____ charge.

a)

neutral

b)

negative

c)

positive

d)

both positive and negative

20.

What is the sum of an atom's protons and neutrons called?

a)

atom

b)

atomic theory

c)

atomic mass

d)

atomic number

21.

The _____ is based on the number of protons in the nucleus of the atom.

a)

atomic structure

b)

periodic table of the elements

c)

atomic number

d)

atomic mass

22.

What subatomic particle is represented by this symbol (+):

a)

neutron

b)

proton

c)

electron

23.

What subatomic particle is represented by this charge (-):

a)

neutron

b)

proton

c)

electron

24.

The chemical formula is C4H10. How many hydrogen atoms are in one molecule of this?

a)

1

b)

4

c)

10

25.

There are three carbon atoms in one formula unit of K2CO3.

a)

true

b)

false

26.

Mg(NO3)2 has five oxygen atoms per formula unit.

a)

true

b)

false

27.

How many molecules are represented by 2C6H12O6 ?

(a)  

28.

How many atoms are in one molecule of C12H22O11 ?

(a)  

29.

How many atoms/ions are in one formula unit of Zn(C2H3O2)2 ?

(a)  

30.

How many carbon atoms are in 3 CH3CH3CH2CH2CH2CH3 ?

(a)  

31.
Explain the difference between an atom and a molecule.
a)
One molecule is made of one atom.
b)
One molecule is always made of different particles.
c)
One molecule is made of more than one atom.
d)
One molecule is made of more than two atoms.
32.
A molecule is made up of ____ or more atoms.
a)
1
b)
2
c)
3
d)
4
33.
How many protons are in this element?
a)
79
b)
196
c)
117
d)
Cannot be determined