Order the following atoms according to increasing atomic radius: Rb, Cl, As, K.

Verified step by step guidance

1. Identify the periodic trend for atomic radius: Atomic radius generally increases as you move down a group and decreases as you move across a period from left to right.
2. Locate each element on the periodic table: Rb (Rubidium) and K (Potassium) are in Group 1, Cl (Chlorine) is in Group 17, and As (Arsenic) is in Group 15.
3. Compare elements within the same group: Rb and K are in the same group, with Rb below K, so Rb has a larger atomic radius than K.
4. Compare elements across periods: Cl is in Period 3, As is in Period 4, K is in Period 4, and Rb is in Period 5. Elements in higher periods generally have larger atomic radii.
5. Order the elements by increasing atomic radius: Start with the smallest atomic radius and proceed to the largest based on their positions in the periodic table.

Key Concepts

Atomic Radius

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

Periodic trends refer to the predictable patterns observed in the properties of elements as you move across or down the periodic table. For atomic radius, the trend shows that elements in the same group have larger radii as you go down, while elements in the same period have smaller radii as you move from left to right due to effective nuclear charge.

Group and Period Positioning

The position of an element in the periodic table, defined by its group (vertical column) and period (horizontal row), significantly influences its atomic radius. For instance, rubidium (Rb) and potassium (K) are in Group 1 and have larger atomic radii compared to chlorine (Cl) and arsenic (As), which are in Groups 17 and 15, respectively, leading to a clear ordering based on their positions.