Carl makes the table below to determine the number of atoms of each element in the chemical formula [tex]\( 4 Ca \left( ClO_3 \right)_2 \)[/tex].

\begin{tabular}{|l|c|c|}
\hline
Element & Calculation & Total atoms \\
\hline
Calcium & [tex]\( 1 \times 4 \)[/tex] & 4 \\
\hline
Chlorine & [tex]\( 1 \times 2 \)[/tex] & 2 \\
\hline
Oxygen & [tex]\( 3 \times 2 \)[/tex] & 6 \\
\hline
\end{tabular}

What mistake did Carl make?

A. He did not multiply the calcium atoms by the subscript 2.

B. He did not add the coefficient 4 to the chlorine and oxygen atoms.

C. He did not add the subscript 2 to the calcium atoms.

D. He did not multiply the chlorine and oxygen atoms by the coefficient 4.



Answer :

Let's carefully analyze the chemical formula [tex]\(4 \, \text{Ca}(\text{ClO}_3)_2\)[/tex] to determine the correct number of atoms for each element and identify Carl's mistake.

The given formula, [tex]\(4 \, \text{Ca}(\text{ClO}_3)_2\)[/tex], contains a coefficient 4, which means there are 4 molecules of [tex]\(\text{Ca}(\text{ClO}_3)_2\)[/tex]. Let's break down the contributions of each element step-by-step:

1. Calcium (Ca):
- Each molecule contains 1 calcium atom.
- Since there are 4 molecules, the total number of calcium atoms is:
[tex]\[ 4 \times 1 = 4 \quad \text{calcium atoms} \][/tex]

2. Chlorine (Cl):
- Each molecule contains [tex]\((\text{ClO}_3)_2\)[/tex], which means 2 chlorine atoms.
- Since there are 4 molecules, the total number of chlorine atoms is:
[tex]\[ 4 \times 2 = 8 \quad \text{chlorine atoms} \][/tex]

3. Oxygen (O):
- Each molecule contains [tex]\(3\)[/tex] oxygen atoms per [tex]\(\text{ClO}_3\)[/tex], and there are 2 [tex]\(\text{ClO}_3\)[/tex] groups in each molecule, so each molecule contains [tex]\(3 \times 2 = 6\)[/tex] oxygen atoms.
- Since there are 4 molecules, the total number of oxygen atoms is:
[tex]\[ 4 \times 6 = 24 \quad \text{oxygen atoms} \][/tex]

By combining these contributions, we can fill in the correct table for each element:

[tex]\[ \begin{array}{|l|c|c|} \hline \text{Element} & \text{Calculation} & \text{Total Atoms} \\ \hline \text{Calcium} & 1 \times 4 & 4 \\ \hline \text{Chlorine} & 2 \times 4 & 8 \\ \hline \text{Oxygen} & 6 \times 4 & 24 \\ \hline \end{array} \][/tex]

Now, let's compare this to Carl's table and find his mistake:
[tex]\[ \begin{array}{|l|c|c|} \hline \text{Element} & \text{Calculation} & \text{Total atoms} \\ \hline \text{Calcium} & 1 \times 4 & 4 \\ \hline \text{Chlorine} & 1 \times 2 & 2 \\ \hline \text{Oxygen} & 3 \times 2 & 6 \\ \hline \end{array} \][/tex]

The correct calculation for chlorine and oxygen atoms involves multiplying by the coefficient 4, which Carl missed. Therefore, Carl's mistake is:

- He did not multiply the chlorine and oxygen atoms by the coefficient 4.

Hence, the correct answer is:
He did not multiply the chlorine and oxygen atoms by the coefficient 4.