esent in the following simple binary ionic compounds.
1. Znl2 ______ 11. CaO _____
2. MgBr2 _____ 12. KF _______
3. Na3N ______ 13. Li3P ______
4. BaO _______ 14. SrS ______
5. Na4Si ______ 15. ZnCI2 ______
6. Zn3N2 _______ 16. K2O ________
7. Al2O3 _______ 17. KCI _______
8. KBR _______ 18. Nal ______
9. RuN ______ 19. La2O3 ________
10. HfO2 ______ 20. Cs2S _______