No, calcium and chlorine do not have the same atoms. They are different elements and therefore have different atomic structures.

Here's why:

* Calcium (Ca) has an atomic number of 20, meaning it has 20 protons in its nucleus.

* Chlorine (Cl) has an atomic number of 17, meaning it has 17 protons in its nucleus.

The number of protons defines an element. Since calcium and chlorine have different numbers of protons, they are distinct elements with different properties.