Periodicity

Periodicity

• Periodicity is trends in the periodic table:
• Elements are classified into s, p and d blocks according to which orbitals have the highest energy electrons. This increases across a period:
• Period 2: Li --------------------> Ne
• Period 3: Na -----------------------> Ar
• The atomic radius of atoms decreases going left to right across a period; the increased number of protons create a greater positive charge which pulls the electrons closer as the amount of shielding stays roughly the same.
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• Caption: The trend for period 2 is exactly the same.

Trends in first ionisation energy