Periodic Table Blocks (s, p, d, f) — Chemistry Mnemonic
Target: mnemonic for s p d f blocks periodic table
Why is this hard to memorize?
The periodic table is divided into four blocks based on the subshell being filled: s-block (Groups 1-2, valence electrons in s-orbital), p-block (Groups 13-18, valence electrons in p-orbital), d-block (Groups 3-12, valence electrons in d-orbital), and f-block (lanthanides and actinides, filling f-orbitals). Knowing which block an element belongs to immediately tells you its properties: s-block elements are reactive metals, p-block spans metals to non-metals to noble gases, d-block are transition metals, and f-block are inner transition metals.
Classic mnemonics you should know
"s-block = left 2 columns. p-block = right 6 columns. d-block = middle 10 columns. f-block = bottom 2 rows."
s-block: Groups 1-2 (2 elements per period). p-block: Groups 13-18 (6 elements per period). d-block: Groups 3-12 (10 elements per period). f-block: 14 elements in each row (4f = lanthanides, 5f = actinides).
"s=2, p=6, d=10, f=14 — "2-6-10-14" — maximum electrons each subshell holds"
The width of each block = maximum electrons in that subshell type. s-orbital holds 2e⁻ → 2 columns. p holds 6 → 6 columns. d holds 10 → 10 columns. f holds 14 → 14 columns. This also tells you how many elements are in each block per period.
"s=Soft metals/reactive. p=Properties vary (metals→non-metals→noble). d=Dense, coloured, catalytic. f=Fairly similar, radioactive (actinides)"
Each block has characteristic properties: s-block metals are soft, low density, highly reactive. p-block spans the entire range. d-block transition metals are dense, coloured, good catalysts. f-block inner transition metals have very similar chemistry within each row.
The complete list
- s-block: Groups 1-2 (2 columns)
- p-block: Groups 13-18 (6 columns)
- d-block: Groups 3-12 (10 columns)
- f-block: Lanthanides + Actinides (14 columns)
- s holds 2e⁻, p holds 6, d holds 10, f holds 14
- Hydrogen is special: in s-block but non-metal
- Helium is in s-block but placed with p-block (Group 18)
Frequently asked questions
Why is Helium in Group 18 (p-block) if it is an s-block element?
Helium has electronic configuration 1s² — it fills the s-orbital, making it technically s-block. But it is placed in Group 18 with noble gases because its properties match: it has a fully filled outer shell (1s²), is a gas, is chemically inert, and has very high ionization energy. Chemical properties trump electronic configuration for placement.
How do I find which block an element belongs to?
Write its electronic configuration. Look at the LAST electron added: if it goes into s-orbital → s-block. p-orbital → p-block. d-orbital → d-block. f-orbital → f-block. Example: Fe = [Ar]3d⁶4s² — last electrons fill 3d → d-block. But note: the "last electron" follows the building-up order, not necessarily the highest energy.
Why do d-block elements show variable oxidation states?
d-block elements have (n-1)d and ns electrons that are close in energy. Both subshells can participate in bonding, allowing multiple oxidation states. For example, Mn can show +2 to +7 because 3d and 4s electrons have similar energies. s-block elements only lose their ns electrons (limited to +1 or +2).
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