* Atomic Number: The atomic number of an element represents the number of protons in its nucleus.
* Periodic Table: The elements are arranged on the periodic table in order of increasing atomic number.
Looking at the periodic table:
* Nitrogen (N): Atomic number 7
* Aluminum (Al): Atomic number 13
* Potassium (K): Atomic number 19
Therefore, Nitrogen (N) has the smallest atomic number.
