Question

question 7
the compound ( pi_3 ) is named
monophosphorus iodide
phosphorus triiodide
phosphorus iodide
potassium iodide
none of these
question 8
1 pts
the correct name for the compound ( sno_2 ) is
______.
tin(iv) oxide
tin oxide
tin dioxide
tin(ii) dioxide
tin(ii) oxide
question 9
1 pts
the correct formula for iron(ii) phosphide is
( fep_2 )
( fe_3p_2 )
( fe_2p_3 )
( fep )
( fe_2p )

Explanation:

• Question 7: For binary covalent compounds (non - metal + non - metal), we use prefixes. The formula \(PI_3\) has one phosphorus (\(P\)) atom (prefix “mono - “ is often omitted for the first element) and three iodine (\(I\)) atoms (prefix “tri - “). So it is named phosphorus triiodide.
• Question 8: Tin (\(Sn\)) is a metal with variable oxidation states. In \(SnO_2\), oxygen has an oxidation state of \(- 2\). Let the oxidation state of \(Sn\) be \(x\). Using the formula \(x+2\times(-2)=0\) (since the compound is neutral), we get \(x = + 4\). So the name is tin(IV) oxide.
• Question 9: Iron(II) has an oxidation state of \(+2\) (\(Fe^{2+}\)), and phosphide (\(P\)) has an oxidation state of \(-3\) (\(P^{3 -}\)). Using the criss - cross method (swap the magnitudes of the charges), we get \(Fe_3P_2\) (\(3\times(+2)+2\times(-3)=0\)).

Answer:

Question 7: phosphorus triiodide
Question 8: tin(IV) oxide
Question 9: \(Fe_3P_2\)