How do you find how many protonsneutrons and electrons are in an atom?

Answer 1

Using the Periodic Table you are able to determine the number of protons, electrons, and neutrons for any of the elements identified to this date. Knowing an element's name or symbol, look up the element in the table. For example lets look up Boron! Boron's chemical symbol is B, and from the periodic table its atomic number is 5. The atomic number of an element reveals the number of protons and also the number of electrons the element has as a single isolated atom. Although, the element may not exist freely as an isolated single atom in nature.

So, Boron has 5 protons and 5 electrons. The number of neutrons an element may have can vary, and this is what differentiates stable and unstable isotopes of many elements. Boron has a molar mass of 10.811, and is listed with two stable isotopes: 10B and 11B. Subtracting the atomic number from the isotope number gives the number of neutrons boron is found with. The 10B isotope has 5 neutrons, and the 11B isotope has 6 neutrons. Since the molar mass is 10.811, we can tell that the 11B isotope is more abundant than the 10B isotope. If the distribution was equal then the molar mass would be 10.5.

Answer 2

The numbers of protons and electrons are given by the atomic number of the element. The Atomic Mass of the isotope of an element gives you the total of the number of protons and neutrons. Subtract the atomic number from the atomic mass to obtain the number of neutrons for that isotope.

Answer 3

The number of protons is given by the atomic number of the element. The number of electrons will be the same as the number of protons. The number of neutrons will be the difference between the atomic number and the atomic mass. An example might be Na (sodium). It has atomic number 11, meaning 11 protons and 11 electrons. It has atomic mass of 23, meaning 12 neutrons (23 - 11 = 12).