What is the trend for ionization energy across a period in the periodic table?
Increases from left to right.
Remains constant
Varies randomly
Decreases from left to right
Correct answer is A
Ionization energy generally increases from left to right across a period. Ionization energy is the energy required to remove an electron from a neutral atom, and as you move from left to right, the atomic size decreases, making it harder to remove an electron, and thus, the ionization energy increases.