how do you determine what the atom of an element looks like by looking at the periodic table?

Question

i know the atomic number is the number of protons, but how do you find out how many neutrons and electrons in it?

Answer 1

http://education.jlab.org/qa/pen_number.html

The atomic number is the number of protons in an atom of an element. In our example, krypton's atomic number is 36. This tells us that an atom of krypton has 36 protons in its nucleus

Atoms must have equal numbers of protons and electrons. In our example, an atom of krypton must contain 36 electrons since it contains 36 protons.

The atomic weight is basically a measurement of the total number of particles in an atom's nucleus.
Mass Number = (Number of Protons) + (Number of Neutrons)

Number of Protons = Atomic Number

Number of Electrons = Number of Protons = Atomic Number

Number of Neutrons = Mass Number - Atomic Number

hope this helps!

Answer 2

The number of electrons is the same as the number of protons. The number of neutrons can vary, and you can get an approximate idea by taking the proton number away from the Ar value, which is also printed in the Periodic Table. This won't give you a whole number usually - I said it was an approximate idea.