Counting Atoms Interactive Slides

Multiple Choice

What does the subscript '2' in H₂S indicate?

• There are two atoms of hydrogen

• There are two atoms of sulfur

• There are two molecules of H₂S

• There are two atoms of oxygen

Open Ended

Why is it important to understand subscripts when studying chemical formulas?

Multiple Choice

What is the role of a coefficient in a chemical formula?

• It shows the number of molecules or compounds present.

• It shows the number of electrons in an atom.

• It shows the number of protons in an atom.

• It shows the number of neutrons in an atom.

Multiple Choice

How do you determine the total number of atoms of each element in a compound when both coefficients and subscripts are present?

• Multiply the coefficient by the subscript for each element.

• Add the coefficient and subscript for each element.

• Multiply the coefficient by the atomic number.

• Add the coefficient to the atomic number.

Multiple Select

Which of the following statements are true about coefficients and subscripts in chemical formulas?

• Coefficients multiply all atoms in the molecule or compound.

• Subscripts only affect the element they follow.

• If there is no subscript, there is only one atom of that element.

• Coefficients only affect the first element in the formula.

Fill in the Blanks

In the formula B2(SO3)3, how many atoms of oxygen are present?

Multiple Choice

In the formula 2(H2O), how many atoms of hydrogen and oxygen are present?

• 4 hydrogen, 2 oxygen

• 2 hydrogen, 4 oxygen

• 2 hydrogen, 2 oxygen

• 4 hydrogen, 4 oxygen

Open Ended

Explain how parentheses affect the calculation of atoms in a chemical formula with coefficients and subscripts.

Open Ended

How many atoms of aluminum and sulfur are present in Al2S3?

Open Ended

How many atoms of hydrogen, sulfur, and oxygen are present in H2SO4?

Multiple Choice

Which of the following is the correct number of atoms for each element in H2SO4?

• 2 hydrogen, 1 sulfur, 4 oxygen

• 1 hydrogen, 2 sulfur, 4 oxygen

• 2 hydrogen, 4 sulfur, 1 oxygen

• 4 hydrogen, 2 sulfur, 1 oxygen

Open Ended

What are the four steps you should follow to count the number of atoms in a compound, according to the instructions provided?

Fill in the Blanks

Fill in the blank: The trick for identifying an element is to look for a capital letter by itself or a capital letter followed by a

letter.

Multiple Choice

According to the steps for working on your own, what is the first thing you should do when given a compound or molecule?

• Look at the given compound or molecule

• Determine which elements are present

• Make a list of all the elements

• Count each element

Open Ended

After learning about subscripts in chemical formulas, what questions do you still have or what would you like to know more about?

Multiple Choice

What is the purpose of a subscript in a chemical formula?

• To indicate the number of atoms of an element

• To show the charge of an ion

• To represent the mass number

• To identify the type of bond