Which of the following is the correct chemical formula for calcium bromide?

• A. CaBr2
• B. CaBr
• C. Ca2Br2
• D. Ca2Br

Answer: (A)

Verified step by step guidance

1. Identify the charges of the ions involved: calcium typically forms a Ca^{2+} ion, and bromine forms a Br^{-} ion.
2. Determine the ratio of ions needed to balance the overall charge to zero. Since calcium has a +2 charge and bromide has a -1 charge, two bromide ions are needed to balance one calcium ion.
3. Write the chemical formula by placing the calcium ion symbol first, followed by the bromide ion symbol with a subscript indicating the number of bromide ions needed to balance the charge.
4. The resulting formula is CaBr_{2}, indicating one calcium ion combined with two bromide ions.
5. Verify that the total positive and negative charges balance out: +2 from Ca^{2+} and 2 × (-1) from 2 Br^{-} ions equals zero, confirming the formula is electrically neutral.