What do oxygen (O) and bromine (Br) have in common? (3 points)They both tend to gain electrons to gain stability.They both have seven valence electrons.They are both halogens.They are both unreactive.

Oxygen (O) and Bromine (Br) are both elements on the periodic table. They both tend to gain electrons to achieve stability. This is because elements strive to fill their outermost electron shell, and gaining electrons can help achieve this.

However, they do not both have seven valence electrons. Oxygen has six valence electrons, while Bromine has seven. Valence electrons are the electrons in the outermost shell of an atom and are involved in forming chemical bonds with other atoms.

Bromine is a halogen, found in Group 17 (VIIA) of the periodic table. Oxygen, on the other hand, is not a halogen. It is found in Group 16 (VIA) and is classified as a chalcogen.

Lastly, neither Oxygen nor Bromine are unreactive. In fact, they are quite reactive. Oxygen is known for its ability to react with many elements and compounds, playing a vital role in combustion reactions. Bromine is also highly reactive and can be harmful or lethal to biological organisms in sufficient quantities.