Question

multiple - choice question
ionization energy ______ across a period
increases because atom is bigger
decreases because the atom is smaller
decreases because the atom is bigger
stays the same
increases because atom is smaller

Explanation:

Ionization energy is the energy required to remove an electron from an atom. Across a period, the atomic number increases, resulting in a greater nuclear charge. This stronger attraction between the nucleus and the out - most electrons makes it harder to remove an electron, so ionization energy increases. Also, atomic size decreases across a period as the effective nuclear charge pulls the electrons closer to the nucleus.

Answer:

increases because atom is smaller