Determine the number of each type of atom in each formula. c. Cr2(SO4)3

Verified step by step guidance

1. Identify the different elements present in the chemical formula Cr2(SO4)3.
2. Recognize that the formula contains chromium (Cr), sulfur (S), and oxygen (O).
3. Determine the number of chromium atoms: The subscript '2' next to Cr indicates there are 2 chromium atoms.
4. Determine the number of sulfate ions (SO4): The subscript '3' outside the parentheses indicates there are 3 sulfate ions.
5. Calculate the total number of sulfur and oxygen atoms: Each sulfate ion (SO4) contains 1 sulfur atom and 4 oxygen atoms, so multiply these by 3 to find the total number of sulfur and oxygen atoms.

Key Concepts

Chemical Formula Interpretation

A chemical formula represents the types and numbers of atoms in a compound. In the formula Cr2(SO4)3, the subscript numbers indicate how many of each atom are present. For example, 'Cr2' means there are two chromium atoms, while '(SO4)3' indicates that there are three sulfate groups, each containing one sulfur and four oxygen atoms.

Subscripts and Parentheses in Formulas

Subscripts in chemical formulas denote the number of atoms of the element directly preceding them. Parentheses are used to group atoms that are part of a polyatomic ion, and when a subscript follows the parentheses, it multiplies the number of each atom within the parentheses. In Cr2(SO4)3, the '3' outside the parentheses means that each atom in the sulfate ion (SO4) is counted three times.

Counting Atoms in Compounds

To determine the total number of each type of atom in a compound, one must carefully analyze the formula. For Cr2(SO4)3, you would count 2 chromium atoms, 3 sulfur atoms (1 from each of the 3 sulfate groups), and 12 oxygen atoms (4 from each sulfate group multiplied by 3). This systematic counting is essential for understanding the composition of the compound.