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Basic3.1.1
The Architecture of the Periodic Table
Understanding the coordinate system of atomic physics: Groups, Periods, and Blocks.
1. The Coordinates
Groups (Vertical)
Elements with the same number of valence electrons.
Significance: Determines chemical properties (bonding behavior).
Periods (Horizontal)
Elements with the same number of occupied electron shells (n).
Significance: Represents the filling of energy levels.
2. The Blocks
The table is divided into blocks based on the highest energy sub-level occupied by the valence electrons.
s-blockGroups 1 & 2
p-blockGroups 13-18
d-blockGroups 3-12
f-blockLanthanoids
3. Metals vs. Non-Metals
The "Staircase Line"
Separates metals from non-metals. It runs diagonally from Boron (B) to Astatine (At). Elements touching this line are Metalloids (e.g., Si, Ge).
| Left Side (Metals) | Right Side (Non-Metals) |
|---|---|
| Large atomic radii | Small atomic radii |
| Low Ionization Energy | High Electron Affinity |
| Form Cations (+) | Form Anions (-) |
| Basic Oxides | Acidic Oxides |
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