Copper, calcium, and bromine are all elements, meaning they are pure substances that cannot be broken down into simpler substances by chemical means. Here are some other commonalities:

* They are found on the periodic table: This is the defining characteristic of an element.

* They are made up of atoms: Each element is composed of atoms with a unique number of protons in their nucleus.

* They can participate in chemical reactions: Elements can combine with each other to form compounds.

However, they also have some key differences:

* Metal, alkaline earth metal, and halogen: Copper is a transition metal, calcium is an alkaline earth metal, and bromine is a halogen. These classifications reflect their different properties and reactivity.

* Physical state at room temperature: Copper is a solid, calcium is a solid, and bromine is a liquid.

* Abundance in the Earth's crust: Copper is more abundant than bromine, but less abundant than calcium.

So, while they share the fundamental characteristics of being elements, their individual properties and behavior are quite distinct.