Fill in the following blanks using larger or smaller, higher orlower. Mg has a atomic size and a ionization energy than Cs.

Atomic size refers to the distance from the nucleus of an atom to the outermost electron shell. Generally, atomic size increases down a group in the periodic table due to the addition of electron shells, making atoms larger. Conversely, atomic size decreases across a period from left to right as the increasing nuclear charge pulls electrons closer to the nucleus.

Ionization energy is the energy required to remove an electron from an atom in its gaseous state. This energy tends to decrease down a group because the outer electrons are farther from the nucleus and experience less attraction. In contrast, ionization energy increases across a period due to the increased nuclear charge, which holds the electrons more tightly.

Periodic trends are patterns observed in the periodic table that describe how certain properties of elements change across periods and down groups. Key trends include atomic size, ionization energy, and electronegativity. Understanding these trends helps predict the behavior of elements, such as why magnesium (Mg) has a smaller atomic size and higher ionization energy compared to cesium (Cs).