Answer:
Explanation:
To find the chemical name for the compound Na2CO3, we will use the list of polyatomic ions and the periodic table.
Polyatomic ion list
First, we need to determine if the compound matches anything on the list of polyatomic ions. This tops the periodic table, so we look at it first.
Many polyatomic ions that end in -ate have oxygen. On our list of polyatomic ions, we might find:
- Nitrate, which is: [tex]NO_{3}^{-}[/tex]
- Iodate, which is: [tex]IO_{3}^{-}[/tex]
- Chlorate, which is: [tex]ClO_{3}^{-}[/tex]
- Carbonate, which is: [tex]CO_{3}^{2-}[/tex]
- Phosphate, which is: [tex]PO_{4}^{3-}[/tex]
We need carbonate, or CO3.
Periodic table
Second, we look at the periodic table to find out what Na represents. See the picture below for the period table, where we find that Na is in the first group (column), third period (row).
Na is short for sodium.
Putting it together, in the same order as the compound Na2CO3, compound chemical name is sodium carbonate.
Nomenclature rule
Why is option C. sodium (II) carbonate incorrect?
We only use brackets with roman numerals for multivalent elements. The valency affects the charge. This is for transition metals on a detailed periodic table. For example, iron, Fe, is multivalent. Iron has a charge of 2+ or 3+ at other times, so we need to clarify.
Iron (II) is [tex]Fe^{2+}[/tex], whereas iron (III) is [tex]Fe^{3+}[/tex].
However, sodium only has one valency, 1+, positive one: [tex]Na^{+}[/tex]
Writing it with (II), positive two, is both unnecessary and incorrect.
Therefore, the correct answer is B. sodium carbonate.
