What is the atomic number of Sodium (Na)?
Q1. What is the atomic number of Sodium (Na)?
Answer: 11
Explanation: Sodium (Na) has 11 protons in its nucleus, giving it atomic number 11; it sits in Period 3, Group 1 of the periodic table. Its single outer-shell electron is readily lost to form the Na⁺ ion, making sodium a highly reactive metal.