The atomic number of the sodium atom is 11. The atomic mass number can be estimated by rounding the atomic mass to 23. From this information, you can find the number of neutrons: 11 protons plus how many neutrons equals a mass number of 23? The number of neutrons would have to be the difference between 23 and 11, which is 12. This fact can be restated this way: 11 protons plus 12 neutrons equals a mass number of 23. For every proton in the nucleus, an electron revolves around the nucleus. Since 11 protons are in sodium, 11 electrons must be in sodium.
The atomic number of the chlorine atom is 17. The atomic mass number can be estimated by rounding the atomic mass to 35. From this information, you can find the number of neutrons, protons, and the number of electrons.
1. How many neutrons are in the chlorine atom?
2. How many electrons are in the chlorine atom?
3. How many protons are in the chlorine atom?