Answer:
Neodymium (Nd)
Explanation:
An element is made up of atom, which contains three subatomic particles namely; proton, electron, and neutron. In a neutral atom, the number of protons determines the atomic number of that element and the atomic number of an element is the identity of that element in the periodic table.
Hence, a change in the proton number of an element means a change in the atomic number and ultimately a change of that element. In this question, Europium (Eu) element with atomic number, 63, loses three protons. This means that that atom now has 60 protons, which denotes the atomic number of another element called Neodymium (Nd).
Therefore, Europium (Eu) element has become Neodymium (Nd) due to loss of protons.