Are you ready to take this lesson's quiz? These questions will help you find out. Make sure you understand why each correct answer is correct—if you don't, review that part of the lesson.
Which polyatomic ion name is correctly matched to its formula?
- carbonate, CO22−
- ammonium, OH−
- sulfate, SO42−
- phosphate, PO33−
Carbonate is CO32−. Carbonite is CO22−.
Ammonium is NH4+. Hydroxide is OH−.
Sulfate is SO42−. Sulfite is SO32−.
Phosphate is PO43−. Phosphite is PO33−.
Which is an example of a ternary ionic compound?
- K3P
- AlPO4
- PCl3
- Ca3P2
This is an example of a binary ionic compound because it is an ionically bonded compound composed of two different elements.
This is an example of a ternary ionic compound because it is an ionically bonded compound composed of three or more different elements.
This is an example of a binary covalent compound because it is a covalently bonded compound composed of two different elements.
This is an example of a binary ionic compound because it is an ionically bonded compound composed of two different elements.
What is the formula for gold (III) chlorate?
- Au3Cl
- Au3ClO3
- AuClO3
- Au(ClO3)3
The Roman numeral represents the charge of the gold ion, not its subscript. Also, chlorate is a polyatomic ion.
The Roman numeral represents the charge of the gold ion, not its subscript.
When writing the formula for an ionic compound, criss-cross the charges, ignoring signs and ones. Remember to use parentheses when the polyatomic ion has an added subscript.
When writing the formula for an ionic compound, criss-cross the charges, ignoring signs and ones. Parentheses are used when the polyatomic ion has an added subscript.
What is the name for Al(NO2)3?
- aluminum nitrite
- aluminum nitrate
- aluminum (III) nitrite
- aluminum (III) nitrate
The aluminum ion is Al3+ and the nitrite ion is NO2−. When these two ions bond together, the formula unit is Al(NO2)3.
The aluminum ion is Al3+ and the nitrate ion is NO3−. When these two ions bond together, the formula unit is Al(NO3)3.
Roman numerals are only necessary for polyvalent metals, such as transition metals. Group 13 metals such as aluminum tend to form only 3+ ions and therefore do not need Roman numerals.
Roman numerals are only necessary for polyvalent metals, such as transition metals. Group 13 metals such as aluminum tend to form only 3+ ions and therefore do not need Roman numerals. Also, nitrate is NO3−, which is not the polyatomic ion present in this compound.
What is the formula for lithium phosphate?
- LiPO4
- Li3PO4
- (Li3)(PO4)
- Li(PO)4
To write the formula for an ionic compound, criss-cross the charges, ignoring signs and ones. The charge of phosphate is 3−.
To write the formula for an ionic compound, criss-cross the charges, ignoring signs and ones.
To write the formula for an ionic compound, criss-cross the charges, ignoring signs and ones. Parentheses are only necessary when the added subscript on a polyatomic ion is greater than 1.
To write the formula for an ionic compound, criss-cross the charges, ignoring signs and ones. Don't break up the formula of a polyatomic ion. Phosphate is PO43−, so the 4 subscript should stay “glued” to the element symbols.
Summary
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