One calcium and two chlorine atoms are near each other. An electron from each atom feels the attraction from the other atom's nucleus. The attraction by the chlorine atoms is stronger than the ...

The atoms in the reactants are: 1 calcium atom, 2 chlorine atoms, 2 sodium atoms, 2 hydrogen atoms, 2 carbon atoms, and 6 oxygen atoms The atoms in the products are: 1 calcium atom, 2 chlorine atoms, ...

The best-known examples are the calcium H and K and the strontium pair (4216, 4077). According to modern theories of spectral emission, these lines are due to an atom which has lost one electron.