1. The atomic number refers to the element and how many electrons an atom may hold, the neutrons determine the isotope, an all together different matter that involves decay rates and sometimes the source of a number of atoms.
1
Fluorine has 9 protons.
2 protons as its atomic number is 2
equal numbers of protons and electrons
There are 6 protons in carbon. The weights of the different isotopes are due to different numbers of neutrons.
Helas, you can not. Just look it up in a proper (periodic) table on ISOTOPES grouped per element. Most commonly the number of neutrons is larger or equal to the number of protons, except for Hygrogen (p=1, n=0).
H2
It still has 7 protons because isotopes of elements have variable NEUTRON numbers, not nucleon (atomic mass) or proton numbers.
It indicates the protons. Periodic table is based on atomic number.
18 protons as its atomic number is 18
No
An osmium atom has 76 protons and 76 electrons, as the number of protons equals the number of electrons in a neutral atom. A niobium atom has 41 protons and 41 electrons. These numbers correspond to their respective atomic numbers on the periodic table.