Explanation:

The Element Having K and L Shell Fully Filled is Neon Neon Has Atomic Number 10. The atomic number is equal to the number of protons in an atom's nucleus. The atomic number determines which element an atom is. For example, any atom that contains exactly 47 protons in its nucleus is an atom of silver. The mass number (symbol A, from the German word Atomgewicht (atomic weight), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus.