Free Printable Counting Atoms in Compounds Quiz

1.

Which of the following is the correct atomic symbol for oxygen?

a)

O

b)

Ox

c)

Oy

d)

Og

2.

How many different elements are present in the compound $H_2O$ ?

a)

1

b)

2

c)

3

d)

4

3.

What is the total number of atoms in a molecule of $CO_2$ ?

a)

1

b)

2

c)

3

d)

4

4.

Which of the following is a compound?

a)

O

b)

H

c)

$H_2O$

d)

N

5.

What does the subscript "2" in $O_2$ represent?

a)

The number of oxygen atoms

b)

The number of molecules

c)

The number of compounds

d)

The number of electrons

6.

Which of the following is NOT an element?

a)

Na

b)

Cl

c)

$NaCl$

d)

O

7.

How many hydrogen atoms are in one molecule of $C_6H_{12}O_6$ ?

a)

6

b)

12

c)

18

d)

24

8.

Identify the number of atoms of each element in $NH_3$ .

a)

1 nitrogen, 3 hydrogen

b)

3 nitrogen, 1 hydrogen

c)

1 nitrogen, 1 hydrogen

d)

3 nitrogen, 3 hydrogen

9.

Which of the following formulas represents a molecule with 2 hydrogen atoms and 1 oxygen atom?

a)

$H_2O$

b)

$HO_2$

c)

$O_2H$

d)

$H_2O_2$

10.

How many Hydrogen atoms are in one molecule of $CH_4$ ?

a)

4

b)

5

c)

1

d)

8

11.

Which of the following best describes the difference between an element and a compound?

a)

Elements are made of one type of atom; compounds are made of two or more types of atoms.

b)

Elements are always gases; compounds are always solids.

c)

Elements are mixtures; compounds are pure substances.

d)

Elements have more atoms than compounds.

12.

Given the formula $CaCO_3$ , how many oxygen atoms are present in one molecule?

a)

1

b)

2

c)

3

d)

4

13.

A student is given the formula $C_2H_6O$ . How many Oxygen atoms are in total in one molecule of this compound? Show your reasoning.

a)

1

b)

2

c)

6

d)

9

14.

You are given two substances: $O_2$ and $H_2O$ . Explain how you can tell which is an element and which is a compound using their formulas.

a)

$O_2$ is a compound because it has two atoms; $H_2O$ is an element because it has three atoms.

b)

$O_2$ is an element because it contains only one type of atom; $H_2O$ is a compound because it contains more than one type of atom.

c)

Both are elements because they have subscripts.

d)

Both are compounds because they have more than one atom.

15.

A molecule has the formula $Al_2SO_4$ . Calculate the total number of oxygen atoms in one molecule. Show your reasoning.

a)

4

b)

8

c)

12

d)

6

16.

How many total atoms are present in one molecule of $H_2SO_4$ ?

a)

5

b)

6

c)

7

d)

8

17.

Which of the following formulas contains exactly two different elements?

a)

$C_6H_{12}O_6$

b)

$H_2O_2$

c)

$NH_3$

d)

$CO_2$

18.

What is the total number of nitrogen atoms in one molecule of $N_2O_5$ ?

a)

5

b)

1

c)

2

d)

3

19.

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

20.

How many different elements are present in this molecule?

3 NH₄C₂H₃O₂

a)

15

b)

36

c)

5

d)

4

Counting Atoms in Compounds Quiz

Total questions: 20

Worksheet time: 20mins

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