Question

using the periodic table, predict the formulas of stable ionic compounds. select three that are correct. a. ko, potassium oxide b. libr₂, lithium bromide c. na₂o, sodium oxide d. bas, barium sulfide e. mgcl₂, magnesium chloride

Explanation:

Step1: Determine potassium ion charge

Potassium (K) is in Group 1, forms K⁺ ion. Oxygen (O) in Group 16 forms O²⁻ ion. For a neutral compound, formula should be K₂O, so A is incorrect.

Step2: Determine lithium ion charge

Lithium (Li) in Group 1 forms Li⁺ ion. Bromine (Br) in Group 17 forms Br⁻ ion. Formula of lithium bromide is LiBr, so B is incorrect.

Step3: Determine sodium ion charge

Sodium (Na) in Group 1 forms Na⁺ ion. Oxygen forms O²⁻ ion. To balance charges, formula is Na₂O, C is correct.

Step4: Determine barium ion charge

Barium (Ba) in Group 2 forms Ba²⁺ ion. Sulfur (S) in Group 16 forms S²⁻ ion. Formula is BaS, D is correct.

Step5: Determine magnesium ion charge

Magnesium (Mg) in Group 2 forms Mg²⁺ ion. Chlorine (Cl) in Group 17 forms Cl⁻ ion. To balance charges, formula is MgCl₂, E is correct.

Answer:

C. Na₂O, sodium oxide
D. BaS, barium sulfide
E. MgCl₂, magnesium chloride