Which element has the greatest ionization energy?

Understand the Problem

The question is asking about the chemical element that possesses the highest ionization energy, which refers to the energy required to remove an electron from an atom in its gaseous state. To find the answer, we will need to refer to periodic trends in chemistry.

More Information

Helium has the highest first ionization energy in the periodic table due to its small atomic radius and high effective nuclear charge, making it extremely difficult to remove an electron.

Tips

A common mistake is assuming larger elements have higher ionization energy; actually, smaller atoms with higher nuclear charge have greater ionization energy.

Sources

• Which element has the highest first ionization energy - socratic.org
• List of Elements in Order of Ionization Energy (eV) - atomicnumber.net