All isotopes of radium have the same number of protons; the number of neutrons is different.
88
The number of protons of an atom is given by its atomic number. Checking the periodic table, we see that the atom with 88 protons is radium. The isotope of radium with 138 neutrons would thus be 226Ra.
Atomic number of uranium: 92 (the same for all the isotopes) Atomic number of an element = number of protons = number of electrons Atomic mass of the isotopes of uranium: 234, 235, 236, 238, 239, 240, ...., etc. Atomoc mass - Atomic number = Number of neutrons
There are 88 protons/electrons in radium. There are 138 neutrons.
Radon has 86 protons, 86 electrons.Rn-222 isotope has 136 (222 - 86 = 136) neutrons
Radium has 88 electrons. The number of neutrons is different for each isotope: Number of neutrons = Atomic mass of an isotope - 88
The number of neutrons is different for each isotope: Number of neutrons = Atomic mass of the isotope - 86 The isotope 222Rn, the most stable (half life = 3,8 days) radon isotope, has 136 neutrons.
Radium has 88 electrons. The number of neutrons is different for each isotope: Number of neutrons = Atomic mass - 88 The most stable and known isotope of radium, 226Ra, has 138 neutrons.
Radium 226 has 88 protons, 88 neutrons, and 138 electrons.