## How many neutrons are in an atom?

For example, silicon has 14 protons and 14 neutrons.

Its atomic number is 14 and its atomic mass is 28.

The most common isotope of uranium has 92 protons and 146 neutrons.

Its atomic number is 92 and its atomic mass is 238 (92 + 146).

2.1 Electrons, Protons, Neutrons, and Atoms.

Elementary Particle | Charge | Mass |
---|---|---|

Proton | +1 | 1 |

Neutron | 1 | |

Electron | −1 | ~0 |

## How do you find protons neutrons and electrons?

Explanation: You can simply subtract the atomic number from the mass number in order to find the number of neutrons. If the atom is neutral, the number of electrons will be equal to the number of protons.

## How do you find the number of atoms?

To calculate the number of atoms in a sample, divide its weight in grams by the amu atomic mass from the periodic table, then multiply the result by Avogadro’s number: 6.02 x 10^23.

## How do you find the number of neutrons without knowing the mass number?

The atomic mass is the weighted average mass of all the isotopes of an element. If we round off the atomic mass to the nearest whole number and subtract the atomic number from it, we get the number of neutrons. That is, number of neutrons = atomic mass (rounded to nearest whole number) – atomic number.