Chem230 Wiki
Advertisement


What is the Diagonal Effect?

- Elements have the tendency to not have characteristics of their own family, but characteristics close to the element that is right one and down one, hence the word diagonal

- Li and Mg

0 3 a.gif

- Be and Al

- B and Si



Why?

- Overall periodic trends cancel each other out

- Down the column

- size increases

- more ionic

- more basic

- less electronegative

- Across the row

- size decreases

- more covalent

- less basic

- more electronegative

- Uniqueness Principle



Caveats:

1) Group relationship (Be to Mg) are dominant over diagonal relationships.

2) B3+, C4+, and Si4+ do not exist as these ionic ideals due to significant covalency.

Advertisement