Diagonal Relationships

Paired Elements: $$\text{Li}-\text{Mg}, \qquad \text{Be}-\text{Al}, \qquad \text{B}-\text{Si}$$

Concept: Highlights the striking chemical similarities existing between certain diagonally adjacent elements of the second and third periods, caused by balancing trends that result in nearly identical ionic potentials (charge-to-size ratios).

Notation:

• $$\text{Ionic Potential } (\phi) = \frac{\text{Ionic Charge}}{\text{Ionic Radius}}$$; Elements share comparable polarizing powers.