Question

Define ionization energy. How would the ionization energy change when electron in hydrogen atom is replaced by a particle 200 times heavier than electron, but having the same charge?

Answer 1

Ionization energy is the minimum energy required to knock out an electron form an atom. Its value will be different for different atoms. Ionization energy will also depend on the orbit form which electron is to be removed.
When an electron in hydrogen atom is replaced by a particle 200 times heavier than electron, but having the same charge, ionization energy will not change, as it depends only on charge and not on mass of particle.