How many outer energy levels do electrons occupy in an atom of sodium (Na)?

Understand the Problem

The question is asking about the electronic structure of sodium, specifically how many energy levels are occupied by electrons in a sodium atom. This relates to the arrangement of electrons around the nucleus and can be determined by looking at the atomic number and electronic configuration of sodium.

More Information

Sodium (Na) has 11 electrons total, arranged in three energy levels: 2 electrons on the first level, 8 on the second level, and 1 electron on the third and outermost energy level. The single electron in the outer level makes sodium highly reactive.

Tips

A common mistake is confusing the number of electrons in the outer energy level with the total number of energy levels an atom has. Ensure you focus on the outermost occupied level.

Sources

• Chapter 4 Lesson 3 - Middle School Chemistry - acs.org
• The periodic table, electron shells, and orbitals - Khan Academy - khanacademy.org