AtomHow do you determine the number of electrons, protons, neutrons in an atom?

Expert Answers
bandmanjoe eNotes educator| Certified Educator

I concur to previous posts.  Each element on the periodic chart has its own square.  At the top of the square is a number called the atomic number, which indicates the number of protons in the atom.  The number of protons is also equal to the number of electrons.  At the bottom of the square is a number called the mass number, which is the weighted average of all known isotopes of the atom.  Subtract the atomic number from this, you get the number of neutrons.

astrosonuthird | Student

Atom is a basic unit of matter that consistes of a dense central neucleus surrounded by a cloud of negatively charged electrons. The name atom comes from a Greek word.


Atom has neucleas in the centre.

The nucleas has neutrons and protons.

The neutrons and protons are further made up of quarks and gluons.

The quarks and glouns are made up of matter and space.

These two fundamental particles was formed 12 billion years ago when the big bang occured.


elekzy | Student

Like said in post #1,

Protons=Electrons=Atomic number

You need to know the number  of protons and the the mass of atoms to determine the number of neutrons

amanda-panda | Student

First you will need a Periodic table of elements. Either that or you need to Know the atomic number and atomic weight of the element.The number of protons in the element is the same as the atomic number. The number of electrons is the same number as the number of protons. The number of neutrons is the atomic weight subtract the atomic number.

Protons=Atomic Number

Electrons=# of Protons

Neutrons=Atomic Weight-Atomic Number