A main group element in period 3
A main group element in period 3 of the periodic table is sodium (Na).
In period 3 of the periodic table, the main group elements are as follows:
1. Sodium (Na) - Atomic Number 11
2. Magnesium (Mg) - Atomic Number 12
3. Aluminum (Al) - Atomic Number 13
4. Silicon (Si) - Atomic Number 14
5. Phosphorus (P) - Atomic Number 15
6. Sulfur (S) - Atomic Number 16
7. Chlorine (Cl) - Atomic Number 17
8. Argon (Ar) - Atomic Number 18
These elements are called main group elements because they belong to the s and p blocks of the periodic table and have similar chemical properties within their respective groups.