Helium atomic mass plus#

The first thing we need to do, is convert the amus into kilograms. So, using Einstein's equation, we see we need kilograms,Īnd we've calculated the mass in amus and so All right, so let's calculate the mass that we're dealing with here. Squared, where E refers to the energy in Joules, M is the mass in kilograms, and C is the speed of light, which is in meters per second, and so you'd be squaring that, so it would be meters So this is the one that most people know. So that's pretty interesting, and we can calculate how much energy, according to Einstein's famous equation, which relates energy and mass. And it looks like we lost some mass here, and really what's happened is the mass, this mass right here, the mass defect, was converted into energy The difference between the predicted mass of the nucleus and theĪctual mass of the nucleus. This is the difference between those two numbers, and All right, so we have the predicted, and then we're going to So if we subtract the actual from the predicted, we can see the difference between those numbers. So let's calculate the differenceīetween those two numbers. Let me go ahead and write this, this is the actual mass, The actual mass of a helium four nucleus has been measured to be 4.00150608 amus. So let me go ahead and write this, this is the predicted mass. This is the predicted mass of the helium four nucleus.

Helium atomic mass plus#

So let's do that math, so this number plus our first number 2.01455294 So 2.0173298 amus, so the mass of a helium nucleus, if we add those two numbers together, we should get that mass. A neutron, one neutron, has a mass in amus of 1.00866490Īnd we have two neutrons, so we have to multiply this number by two.

Get out the calculator, and let's do that, so 1.00727647 times two gives us 2.01455294 so this is equal to 2.01455294, remember theseĪre amus, atomic mass units. The expected mass of a helium four nucleus, and the mass of a proton in amus, atomic mass units, is equal to 1.00727647Īnd we have two protons, so we need to multiply this number by two.

And so, if we know the mass of a proton, and the mass of a neutron, we could easily calculate Number from the mass number, four minus two gives us two neutrons. Well first we need to figure out what's in the nucleus, so, with an atomic number of two, we know there are two Wanted to calculate the mass of a helium four nucleus, Also because the strong interactions limited effect range it only affects adjacent protons/neutrons where the electromagnetic force is a long range force as the atomic nucleus gets larger the electromagnetic force builds up more that the strong interaction's force making them less well held together and once you get to the size of iron it takes more energy to force it together than is released by the binding so this is why stars can't fuse elements beyond iron in their normal fusion process.

The decrease of the strength of the strong interaction at distances greater than the radius of a proton is why more energy is not needed to break up a nucleus. These particles are able to carry this force to about 2.5 fm but it is not until about 1.7 fm that it becomes stronger than the electromagnetic force. This interaction is about 137 times stronger than the electromagnetic interaction.ĭistances greater than 0.8 fm are too far for the gluon interactions so the interaction is carried by particles call pi mesons or pions. At distances less than 0.8 * 10^-15 m or 0.8 fm (femtometer), the radius of a proton or neutron, the strong interaction is directly between quarks carried by particles gluons. The strong interaction has different effects at different ranges.