Understanding ionization energy
Ionization energy measures the energy required to remove an electron from a gaseous atom or ion under a precise convention.
Start with the idea
Ionization energy measures the energy required to remove an electron from a gaseous atom or ion under a precise convention.
A concrete example
A high ionization energy means the electron is hard to remove, not that the atom is ‘more energetic’ in every possible sense.
Mendeleev’s tip
Do not start with a formula. Identify what changes, what stays constant and which quantity you are trying to explain or calculate.
Go one step deeper
Successive ionizations are especially revealing: a large jump can indicate that removal has reached an inner-shell electron.
A trend or model is not an exceptionless law. Always check the quantity’s definition and the conditions being compared.
Check your understanding
Can you explain the phenomenon in your own words before looking at an equation?