To determine which element has the least protons in its nucleus, we need to look at the atomic numbers in the given table. The atomic number of an element represents the number of protons in the nucleus of an atom of that element.
Let's examine each element and their corresponding atomic number:
1. Oxygen has an atomic number of 8.
2. Lithium has an atomic number of 3.
3. Hydrogen has an atomic number of 1.
4. Carbon has an atomic number of 6.
The atomic number that is the least among these is 1, which corresponds to Hydrogen. Therefore, the element with the least protons in the nucleus is:
Hydrogen.
