What is the ratio of Sr raised to the 2 plus power ions to Br raised to the negative power ions in a neutral compound?

A neutral compound must have equal total positive and negative charge. Each Sr²⁺ ion contributes a +2 charge, while each Br⁻ ion contributes a −1 charge, so two bromide ions are needed to balance one strontium ion. The ratio of Sr²⁺ ions to Br⁻ ions is therefore 1 to 2, choice D.

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