subtract the atomic number (#of protons, it's on ur periodic table) from the Atomic Mass (it's usually a decimal, also on ur Periodic Table.)
this will give u the number of neutrons.
the atomic mass is PROTONS + NEUTRONS
To calculate the number of neutrons in an atom of potassium-40, subtract the atomic number (which is 19 for potassium) from the mass number (which is 40 for potassium-40). So, 40 (mass number) - 19 (atomic number) = 21 neutrons in potassium-40.
The number of neutrons in any element depends on the isotope of the element you are referring to. Potassium has 24 isotopes, ranging from 32K to 55K. The most stable natural isotope is 39K, which would have 20 neutrons.
The nomenclature "potassium-19" is not commonly used because it is redundant. The 19 in potassium-19 would indicate the number of protons in potassium. All isotopes of potassium have 19 protons. Therefore 19 is known as the atomic number of potassium. Potassium-41 is one of the three naturally occurring isotopes of potassium. It has 19 protons and 22 neutrons, giving it an atomic mass number of 41.
The mass number of an atom is the total number of protons and neutrons in its nucleus. For an atom with a mass number of 19, it would have 19 total protons and neutrons combined. This atom could be potassium-40 (19 protons and 21 neutrons) or calcium-40 (20 protons and 20 neutrons), for example.
Potassium 31 is potassium's normal state, the way you would find it on the Periodic Table. I presume potassium 41 is an isotope of potassium. (An isotope is the same atom, but it has a different number of neutrons, so the mass differs.)
The mass number is always the sum of the numbers of protons and neutrons and therefore is 39 in this instance. The atomic number of 19 shows that the atom is of the element potassium, and its symbol is 39K.
I'm not sure... but as soon as I figure out the answer I will post the answer... sorry. This answer is better than the one the person before me posted... They said poop and I thought that that was not a true answer for sure and it's nothing to play about and to put a fake answer on here :)
To find the atomic mass, subtract the atomic number (protons) from the mass number (protons + neutrons). Atomic mass = Mass number - Atomic number Atomic mass = 19 - 9 Atomic mass = 10amu So, an atom with an atomic number of 9 and a mass number of 19 would have an atomic mass of 10 atomic mass units (amu).
Potassium has an atomic number of 19 and a mass number close to 39. To draw an atom of potassium, its important to know the following:Atomic number = number of protons = number of electronsMass number = number of protons + number of neutronsFrom this, we can work out the number of protons, neutrons and electrons in potassium:Protons in potassium = 19Electrons in potassium = 19Neutrons in potassium = 20Now, the protons and neutrons are located in the center of an atom called the nucleus so you would need to draw 19 protons and 20 neutrons at the center of the atom. Surrounding the nucleus are electrons that are located in sub-atomic shells. The electrons exist in an order that is called the electronic configuration. For the first 20 elements, the electronic configuration is 2, 8, 8, 2. You would therefore need to draw 4 "rings" around the nucleus. These rings will act as your sub-atomic shells. In the first ring, you would draw 2 electrons, followed by 8 electrons in the second and third ring, and finally 1 electron in the fourth ring.
Mass number = No. of protons + No. of neutrons = 19 + 20 = 39
You would subtract the atomic number from the mass number.
How many neutrons would it have if it had 11 neutrons? 11.