* Protons define the element: The number of protons in an atom's nucleus is its atomic number, and this number uniquely identifies the element.

* Looking up atomic numbers: You can find the atomic numbers of elements on the periodic table.

Let's look up the atomic numbers:

* Silicon (Si): Atomic number 14

* Sulfur (S): Atomic number 16

* Calcium (Ca): Atomic number 20

* Neon (Ne): Atomic number 10

Answer: Calcium (Ca) has the most protons with an atomic number of 20.