Lead
The number of protons in an element is called the atomic number.
The number of protons in an atom is its atomic number.
Boron has 5 protons
Calcium: The identity of an element is determined by how many protons each atom of the element has, and calcium is the name of the element with 20 protons per atom.
Boron
it's Uranium
All atoms contain protons and neutrons (with the only exception of the 1H atom, which has only a single proton).
The atomic number of the element refers to the number of protons of an atom: all atoms of an element have this number of protons. A neutral atom of the element will have the same number of electrons.
Protons and neutrons exist in the nucleus of an atom. The electrons in an atom exist outside the nucleus. All elements have at least one proton; in fact the number of protons, which are positively charged, determines which element it is. Normally, all the elements except hydrogen (H) also contain neutrons, which have no charge (they're neutral, hence their name.)
The number of protons in an atom's nucleus determines its identity and is used to identify the element.
Lead (Pb)
Number of protons + Number of neutrons = Mass number(number of nucleons)