Which of the following pairs of elements can form ionic compounds?
A. sulfur and chlorine
B. cesium and bromine
C. bromine and sodium
D. barium and oxygen
E. sodium and calcium
F. nickel and fluorine

• A. B, C, D, F
• B. A, C, D
• C. B, D, E, F
• D. A, B, E, F
• E. B, C, D

Answer: (A)