Science Question. Atom ?

Question

If the atomic number on the periodic table means how many protons you have.. how do you know how many electrons and neutrons are there?

Im doing a project on Potassium. the atomic number is 19.

please&thanks.

Answer 1

In a stable atom, not an ion, the # of electrons equals the # of protons, so potassium would have 19 protons, and 19 electrons. Protons and Neutrons make up the atomic weight of the atom, so you take the atomic weight and subtract the atomic # and you are left with # of neutrons. 39.0938-19=20 because you round, you can't have a fraction of a neutron. Therefore, there are 20 neutrons, 19 electrons, and 19 protons.

Answer 2

The atomic number will always tell you the number of protons in the atom. The atomic number of potassium is 19, so it has 19 protons. It will always have 19 protons.

Atoms have different isotopes. An isotope is an atom of an element with a different atomic mass. The most common isotope of potassium is 39K. Since the atomic number is 19, there would be 20 neutrons in most potassium atoms. The other natural potassium isotope is 41K, which contains 19 protons and 22 neutrons. The isotope 40K is radioactive and decays into argon.

The charge will tell you the number of electrons. Remember that protons are positively charged while electrons are negatively charged. For example, if potassium is neutral, it contains 19 electrons. If it has a positive charge, it has lost an electron and therefore has 18.

Answer 3

Hi, lets take potassium as a eg for this. The atomic number, z = 19, right? (z is the SI unit for atomic no.) Ok, as you said z also equals the number of protons in an atom. In this case it is 19. To make a stable isotope (one version of many K atoms) found in the periodic table, the same number of electrons are need hence 19 electrons are needed. Why? This has an overall zero charge on the atom.
Now to calculate the number of neutrons you must take away the atomic mass, m, from z giving you 20 neutrons (39-19). I hope that answers the question!

Answer 4

In the neutral atom, the number of electrons = the number of protons. The number of neutrons can vary: this defines the isotope of the element Potassium 40, for example has 40 - 19 = 21 neutrons.

Answer 5

The atomic number also will tell you the number of ELECTRONS in the NEUTRAL ATOM. For example, the atomic number of neutral atom K, Potasssium, is 19, then there are 19 protons and also 19 electrons. But in ionic K plus one; then there r nineteen protons qnd eighteen electrons:

You need the nqss nu,ber to get the neutrons: For ex; forty; then forty less nineteen is your NEUTRONS/

Answer 6

atmoic number = # of protons
mass number = # protons + # nuetrons

and the number of protons = number of electrons

So, potassium has:
19 protons and 19 electrons

Answer 7

well the atomic number tells how many protons and how many electrons it has so potasium has 19 protons and 19 electrons