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Counting Atoms in Compounds

A Grade 8 science worksheet focused on understanding and counting atoms in various chemical compounds, aligning with fundamental chemistry principles.

Grade 8 Science ChemistryCounting Atoms in Compounds
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Includes

Fill in the BlanksMultiple Choice2 Short AnswerTrue / False

Standards

MS-PS1-1MS-PS1-2

Topics

chemistryatomscompoundssciencegrade 8
7 sections · Free to use · Printable
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Counting Atoms in Compounds

Name:

Date:

Score:

Read each question carefully and follow the instructions to count the atoms in the given chemical compounds. Remember to pay attention to subscripts and coefficients.

1. The small number written after an element symbol in a chemical formula is called a  .

2. A large number written in front of a chemical formula is called a   and it multiplies all the atoms in the formula.

3. If there is no subscript written after an element, it means there is only   atom of that element.

1. How many oxygen atoms are in the compound H₂O?

a

1

b

2

c

3

d

4

2. What is the total number of atoms in one molecule of CO₂?

a

1

b

2

c

3

d

4

Count the number of each type of atom in the following compounds:

1. NaCl (Sodium Chloride)

Sodium atoms:  

Chlorine atoms:  

2. H₂SO₄ (Sulfuric Acid)

Hydrogen atoms:  

Sulfur atoms:  

Oxygen atoms:  

3. 2H₂O (Two molecules of Water)

Hydrogen atoms:  

Oxygen atoms:  

1. The chemical formula for carbon dioxide is CO.

T

True

F

False

2. A coefficient of '3' in front of a chemical formula means there are 3 molecules of that compound.

T

True

F

False

Determine the total number of atoms for each element in 3Ca(NO₃)₂. Show your work.