Multiple Choice
Which of the following is the correct chemical formula for a compound composed of aluminum ions and sulfate ions?
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3. Chemical Reactions
Writing Ionic Compounds
Multiple Choice
Which of the following is the correct chemical formula for the ionic compound rubidium cyanide?
A
RbCN
B
Rb2CN
C
Rb(CN)2
D
RbCNO
Verified step by step guidance1
Identify the ions involved in the compound: rubidium (Rb) is a Group 1 metal that forms a +1 cation (Rb\^{+}), and the cyanide ion (CN\^{-}) is a polyatomic ion with a -1 charge.
Recall that ionic compounds are electrically neutral, so the total positive charge must balance the total negative charge.
Since rubidium has a +1 charge and cyanide has a -1 charge, they combine in a 1:1 ratio to balance the charges.
Write the formula by placing the cation first followed by the anion without any subscripts because the charges are already balanced: RbCN.
Verify that the formula represents a neutral compound by confirming the sum of charges: (+1) + (-1) = 0, which means the formula RbCN is correct.
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