Answer;
- rubidium
- arsenic
- silicon
- antimony
Step-by-step explanation;
Bases are substances that react with acids and neutralize them. They are usually metal oxides, metal hydroxides, metal carbonates or metal hydrogen carbonates.
Therefore; Bases are usually:
- metal oxides, such as copper oxide
- metal hydroxides, such as sodium hydroxide, or
- metal carbonates, such as calcium carbonate
Many bases are insoluble - they do not dissolve in water. However, if a base does dissolve in water, we also call it an alkali.