How many protons and neutrons are in the nucleus of lead (Pb)?
The atomic weight of lead (pb) is is 207, meaning that there is a total of 207 protons and neutrons in its nucleus. Since its atomic number is 82, there are 82 protons in its nucleus. Therefore, there are 125 (207 – 82) neutrons in its nucleus. 10. Identify one element that has the same number of protons and neutrons its nucleus. Both oxygen (8 protons and 8 neutrons) and nitrogen (7 protons and 7 neutrons) have the same number of protons and neutrons. 11. What elements on the periodic table is the only element that has no neutrons in its nucleus? Hydrogen (H) has an atomic weight that is equal to its atomic number (1). Therefore it can only have 1 proton in its nucleus and no neutrons. 12. The universe is essentially composed of 2 elements, hydrogen and helium. There is one major, familiar exception to this “rule”. What is it? The Earth and other terrestrial planets. The density of the Earth is 5.515 grams/cubic centimeter. The average density of the terrestrial planets is 5.03 grams/
