20 electrons 20 protons 20 neutrons contains an atom ..

To determine the number of electrons, protons and neutrons in an atom, one must refer to the periodic table of chemical elements of D.I. Mendeleev.

Our ordinal number is responsible for the number of electrons in an atom.

The serial number “20” has the substance “Ca”.

To find the number of neutrons, you need to do the following:

1) determine the atomic mass of the substance according to the table. For calcium, it is 40.

2) subtract the serial number from the atomic mass.

40 – 20 = 20 – the number of neutrons.

And the number of protons is equal to the number of neutrons. I mean, there are also 20 of them.