Because the mass of electron is negligible when compared to the mass of protons or neutrons.
The atomic number must be known along with the mass number. Then the number of protons or electrons is the same as the atomic number, and the number of neutrons is the difference between the mass number and the atomic number.
Potassium-43 has 19 protons, 24 neutrons, and 19 electrons. The number of protons and electrons is determined by the element's atomic number (which is 19 for potassium), while the number of neutrons is calculated by subtracting the atomic number from the isotope mass number.
In a neutral atom of 243Am (Americium), there are 95 protons (which corresponds to its atomic number), approximately 148 neutrons (which can be calculated by subtracting the atomic number from the atomic mass), and 95 electrons (equal to the number of protons in a neutral atom).
The charge of an ion can be calculated by adding up the protons and subtracting the electrons. When oxygen with 8 protons has 8 electrons it is neutral, when it has 7 electrons it is positively charged.
Number of protons = Number of electrons = Atomic number Number of neutrons = Atomic number - Number of protons
No. The number of neutrons has no affect on the number of protons and electrons.
The number of protons in the nucleus of an atom determine its atomic number, while the number of neutrons and electrons can vary based on the specific isotope. In a neutral atom, the number of electrons is equal to the number of protons. The number of neutrons can be calculated by subtracting the atomic number from the atomic mass.
there are 7 neutrons, 7 protons, and....----electrons
Americium has 95 protons and electrons. Number of neutrons: atomic mass of an isotope - number of protons
Carbon-12 has 6 protons, 6 neutrons, and 6 electrons. The number of protons determines the element (carbon), the number of neutrons plus protons gives the mass number (12), and in a neutral atom, the number of electrons equals the number of protons.
Boron has 5 electrons and protons; the number of neutrons is specific for each isotope. Number of neutrons in a boron isotope = Mass number - 5
Uranium isotopes have 92 protons and electrons; the number of neutrons is different for each isotope.Number of neutrons = Mass number - Number of protons