Question

Predict the empirical formulas of the ionic compounds formed from the following pairs of elements. Name each compound. a. $\mathrm{Li}$ and $\mathrm{N}$ c. $\mathrm{Rb}$ and $\mathrm{Cl}$ b. Ga and $\mathrm{O}$ d. $\mathrm{Ba}$ and $\mathrm{S}$

Short answer

The empirical formulas and names of the ionic compounds are: a. ${\mathrm{Li}}_3\mathrm{N}$: Lithium nitride c. $\mathrm{RbCl}$: Rubidium chloride b. ${\mathrm{Ga}}_2{\mathrm{O}}_3$: Gallium oxide d. $\mathrm{BaS}$: Barium sulfide

Step-by-step solution

Identify the charges of the ions

Find the charges of the ions formed by the given elements. Elements in group 1 form +1 ions, group 2 form +2 ions, group 13 form +3 ions, group 15 form -3 ions, group 16 form -2 ions, and group 17 form -1 ions. a. Li is in group 1 (+1 ion) and N is in group 15 (-3 ion) c. Rb is in group 1 (+1 ion) and Cl is in group 17 (-1 ion) b. Ga is in group 13 (+3 ion) and O is in group 16 (-2 ion) d. Ba is in group 2 (+2 ion) and S is in group 16 (-2 ion)

Determine the empirical formula based on ion charges

Determine the ratio of cations to anions to create a neutral compound. The compound's empirical formula will have the lowest whole-number ratio of elements. a. Li (+1) and N (-3): We need three Li ions to balance one N ion, so the formula is ${\mathrm{Li}}_3\mathrm{N}$. c. Rb (+1) and Cl (-1): We need one Rb ion to balance one Cl ion, so the formula is $\mathrm{RbCl}$. b. Ga (+3) and O (-2): We need two Ga ions to balance three O ions, so the formula is ${\mathrm{Ga}}_2{\mathrm{O}}_3$. d. Ba (+2) and S (-2): We need one Ba ion to balance one S ion, so the formula is $\mathrm{BaS}$.

Name each compound

Following the IUPAC naming rules, name each compound, using the names of the cation followed by the anion. For the anion, use the ending -ide. a. ${\mathrm{Li}}_3\mathrm{N}$: Lithium nitride c. $\mathrm{RbCl}$: Rubidium chloride b. ${\mathrm{Ga}}_2{\mathrm{O}}_3$: Gallium oxide d. $\mathrm{BaS}$: Barium sulfide