# 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 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 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) | Block | Groups | Valence Sub-shell | Common Name / Type | | :--- | :---: | :---: | :--- | | **s-Block** | 1, 2 | s | Alkali & Alkaline Earth Metals | | **p-Block** | 13 - 18 | p | Metals, Non-metals, Metalloids | | **d-Block** | 3 - 12 | d | Transition Metals | | **f-Block** | N/A | f | Inner Transition Metals (Lanthanides & Actinides) | **Significance:** Understanding the block structure is fundamental to predicting an element's chemical behavior, reactivity, and bonding characteristics. It is closely tied to the .