Question

correctly name the compound $ba_3p_2$.
a barium phosphide
b tribarium diphosphide
c barium(ii) phosphide
d barium phosphorus

Explanation:

To name the ionic compound \( Ba_3P_2 \), we first identify the ions. Barium (\( Ba \)) is an alkaline earth metal, so it forms \( Ba^{2+} \) ions. Phosphorus (\( P \)) forms the phosphide ion (\( P^{3-} \)) in ionic compounds. The formula \( Ba_3P_2 \) is formed by the combination of \( 3 \, Ba^{2+} \) and \( 2 \, P^{3-} \) to balance the charges (\( 3\times(+2) + 2\times(-3) = 0 \)). For ionic compounds with a metal that has only one common charge (like barium, which is always \( +2 \)), we use the name of the metal followed by the name of the non - metal ion with the suffix “-ide”. So the name is barium phosphide. Option b is incorrect because we don't use prefixes for ionic compounds formed from elements with a single common charge (we use prefixes for molecular compounds or ionic compounds with metals having variable charges, but barium doesn't have variable charges here). Option c is incorrect because barium only has a \( +2 \) charge, so we don't need to specify the charge in parentheses. Option d is incorrect as “barium phosphorus” is not the correct naming convention for this ionic compound.

Answer:

a. barium phosphide