Question

a student has a compound of cateo₃
the student wants there to be a total of
5 o (oxygen) atoms
5 ca (calcium) atoms
5 te (tellurium) atoms
which of the following best explains how the student can acquire those atom totals given the compound provided?
place a coefficient of 2 after the ca.
place a subscript of 5 after the o.
place a coefficient of 5 before the ca.
place a subscript of 15 before the ca.

Explanation:

Step1: Analyze the compound formula

The formula \(CaTeO_3\) has 1 \(Ca\), 1 \(Te\), and 3 \(O\) atoms.

Step2: Consider the effect of coefficients

A coefficient multiplies the number of each atom in the formula. If we put a coefficient of 5 before \(CaTeO_3\) (i.e., \(5CaTeO_3\)), we get \(5\times1 = 5\) \(Ca\) atoms, \(5\times1 = 5\) \(Te\) atoms, and \(5\times3 = 15\) \(O\) atoms. But wait, the problem might have a typo in the options. If we assume the formula is \(CaTeO_3\) and we want 5 of each atom:

• Placing a coefficient of 2 after \(Ca\) (invalid notation, coefficients are before the formula) won't work.
• Placing a subscript of 5 after \(O\) (\(CaTeO_5\)) changes the formula and doesn't give 5 \(Ca\) and \(Te\).
• Placing a coefficient of 5 before \(CaTeO_3\) (even though the option says "before the Ca" which is part of the formula) gives 5 \(Ca\), 5 \(Te\), and 15 \(O\) (if we assume the student made a mistake in counting \(O\) requirements or it's a mis - phrased option). The other options are clearly wrong. A subscript of 15 before \(Ca\) is invalid notation.

So the best (albeit with some notational assumption) is to place a coefficient of 5 before the \(Ca\) (as part of the formula \(CaTeO_3\)).

Answer:

Place a coefficient of 5 before the Ca.