Identify each statement as true or false: (a) Ionization energies are always endothermic. (b) Potassium has a larger first ionization energy than lithium. (c) The second ionization energy of the sodium atom is larger than the second ionization energy of the magnesium atom. (d) The third ionization energy is three times the first ionization energy of an atom.

Ionization energy is the energy required to remove an electron from a gaseous atom or ion. This process is typically endothermic, meaning it absorbs energy, as energy must be supplied to overcome the attraction between the negatively charged electron and the positively charged nucleus.

Ionization energy generally increases across a period in the periodic table due to increasing nuclear charge, which holds electrons more tightly. Conversely, it decreases down a group as additional electron shells are added, increasing distance from the nucleus and electron shielding, making it easier to remove an electron.

The first ionization energy refers to the energy needed to remove the first electron, while subsequent ionization energies (second, third, etc.) are typically higher due to increased positive charge in the ion, which makes it harder to remove additional electrons. However, the relationship between these energies is not linear, and the third ionization energy is not simply three times the first.