Final answer:
The number of protons in an atom's nucleus defines the element and its atomic number, with Carbon having 6, Hydrogen 1, Oxygen 8, Phosphorus 15, and Calcium 20 protons.
Step-by-step explanation:
The number of protons in an element's nucleus is unique to that element and is known as the element's atomic number. Here are the numbers of protons for the elements as requested:
- Carbon (C) has 6 protons.
- Hydrogen (H) has 1 proton.
- Oxygen (O) has 8 protons.
- Phosphorus (P) has 15 protons.
- Calcium (Ca) has 20 protons.
Each element is defined by its atomic number, which is why these numbers are consistent for each of these elements regardless of their isotope or molecular form.