Arrange the following elements in order of increasing atomic radius: (a) Rb (b) F (c) Sb (d) S.

Atomic radius is a measure of the size of an atom, typically defined as the distance from the nucleus to the outermost electron shell. It varies across the periodic table, generally increasing down a group due to the addition of electron shells and decreasing across a period due to increased nuclear charge, which pulls electrons closer to the nucleus.

Periodic trends refer to predictable patterns in the properties of elements as you move across or down the periodic table. Key trends include atomic radius, ionization energy, and electronegativity. Understanding these trends helps in predicting the behavior of elements, such as how their atomic radii change with position in the table.

Elements are organized in groups (columns) and periods (rows) in the periodic table. Elements in the same group share similar properties and have the same number of valence electrons, while elements in the same period have the same number of electron shells. This organization is crucial for understanding atomic size, as elements in lower periods have larger atomic radii due to additional electron shells.