Classification (Inorganic Chemistry)
Specification Reference Inorganic chemistry, Periodicity 3.2.1.1
Quick Notes
- Elements are classified according to their positions in the periodic table, which is determined by their proton numbers and electronic configurations.
- Main classifications:
- s-block elements (Groups 1 and 2, alkali and alkaline earth metals).
- p-block elements (Groups 13-18, includes non-metals, halogens, and noble gases).
- d-block elements (Transition metals, variable oxidation states, coloured compounds).
- f-block elements (Lanthanides and actinides, rare earth metals).
Full Notes
Periodic Table Classification
Elements are arranged in the periodic table based on atomic number and electronic configuration.
The table is divided into blocks based on the highest-energy sub-shell occupied by electrons (see electron configurations).
The periodic table is arranged in periods (rows) and groups (columns). The group number of an element is the same as the number of electrons an atom of the element has in its outermost shell. The period number of an element is the same as the number of energy levels or ‘shells’ an atom of the element has.
Example properties of Elements by Blocks
| Block | Groups Included | Properties | Example Elements |
|---|---|---|---|
| s-block | Groups 1–2 | Highly reactive metals, low ionization energy, form basic oxides | Na, Mg |
| p-block | Groups 13–18 | Contains metals, non-metals, and metalloids; includes noble gases | C, O, Cl, Ne |
| d-block | Transition metals (Groups 3–12) | Form colored compounds, variable oxidation states, good catalysts | Fe, Cu, Zn |
| f-block | Lanthanides & Actinides | Rare earth elements; radioactive elements in actinides | U, Ce |
Summary
- Positions in the periodic table are determined by proton number and electronic configuration.
- The periodic table is divided into s-, p-, d-, and f-blocks according to the highest-energy sub-shell occupied.
- Groups indicate the number of outermost electrons; periods indicate the number of occupied shells.