Question

write the chemical formula for the ionic compound of calcium ion and sulfate ion. caso3 ca(so4)2 caso4 caco3 write the chemical formula for the ionic compound of iron (iii) ion and nitrate ion? fe(no2)3 fe(no3)2 feno3 fe(no3)3 write the chemical formula for sulfur hexafluoride. sf6 sci2 fs6 sf5

Explanation:

First question:

Step1: Determine the charges

Calcium ion (\(Ca^{2+}\)) has a charge of \(+2\), sulfate ion (\(SO_{4}^{2 -}\)) has a charge of \(-2\).

Step2: Balance the charges

Using the criss - cross method, since the magnitudes of the charges are equal (\(2\)), the formula is \(CaSO_{4}\). \(CaSO_{3}\) is calcium sulfite (sulfite ion is \(SO_{3}^{2-}\)), \(Ca(SO_{4})_{2}\) would imply incorrect charge balancing (\(+2\) and \(- 2\) don't need a subscript \(2\) on sulfate), and \(CaCO_{3}\) is calcium carbonate (carbonate ion is \(CO_{3}^{2-}\)).

Second question:

Step1: Determine the charges

Iron(III) ion (\(Fe^{3+}\)) has a charge of \(+3\), nitrate ion (\(NO_{3}^{-}\)) has a charge of \(-1\).

Step2: Balance the charges

Using the criss - cross method, for \(Fe^{3+}\) and \(NO_{3}^{-}\), we need three \(NO_{3}^{-}\) ions to balance the \(+3\) charge of \(Fe^{3+}\). So the formula is \(Fe(NO_{3})_{3}\). \(Fe(NO_{2})_{3}\) is iron(III) nitrite (nitrite ion is \(NO_{2}^{-}\)), \(Fe(NO_{3})_{2}\) would imply \(Fe^{2+}\) (iron(II)), and \(FeNO_{3}\) has incorrect charge balancing.

Third question:

Step1: Analyze the name

"Sulfur hexafluoride" means one sulfur (\(S\)) atom and six fluorine (\(F\)) atoms.

Step2: Write the formula

The formula is \(SF_{6}\). \(SCl_{2}\) is sulfur dichloride, \(FS_{6}\) has the elements in the wrong order (the less electronegative element is usually written first in binary covalent compounds), and \(SF_{5}\) has the wrong number of fluorine atoms.

Answer:

1. \(CaSO_{4}\)
2. \(Fe(NO_{3})_{3}\)
3. \(SF_{6}\)