10.2 Blocks of Elements in the Periodic Table

The periodic table is organized into blocks based on the sub-shell where an element's outermost (valence) electrons are located. There are four main blocks corresponding to the s, p, d, and f sub-shells.

This block structure builds upon the organization of Rules of Electronic Configuration→ and the general layout of the periodic table.

s-Block

The s-block elements are located on the far left of the periodic table.

• Groups: 1 and 2 (with the exception of Helium, He).
• Valence Electrons: Occupy the s-sub shell.
• Element Types:
  • Group 1: Alkali Metals
  • Group 2: Alkaline Earth Metals

p-Block

The p-block elements are found on the right side of the periodic table.

• Groups: 13 to 18.
• Valence Electrons: Occupy the p-sub shell.
• Element Types: This block is diverse and contains a mix of metals, non-metals, and metalloids. It also includes the Halogens→ in Group 17.

d-Block

The d-block elements are located in the central part of the periodic table, bridging the s-block and p-block.

• Groups: 3 to 12 (also known as sub-group B).
• Valence Electrons: Occupy the d-sub shell.
• Element Types: These elements are known as the transition metals.

f-Block

The f-block elements are typically shown as two separate rows at the bottom of the periodic table.

• Location: Two series detached from the main body of the periodic table to keep the table from becoming too wide.
• Valence Electrons: Occupy the f-sub shell.
• Element Types: Also known as inner transition metals, they are divided into two series:
  • Lanthanides (Atomic numbers 58-71)
  • Actinides (Atomic numbers 90-103)

Significance: Understanding the block structure is fundamental to predicting an element's chemical behavior, reactivity, and bonding characteristics. It is closely tied to the Determination of Electronic Configuration→.