Why would the relative atomic mass be the number of neutrons and the number of protons

The relative atomic weight is taken as 1 12 of the c(12) atom as a unit to measure the mass of the atom. c(12) has 6 protons and 6 neutrons.

The mass of the atoms is concentrated in the nucleus, that is, the branches and neutrons (the mass of the electrons is small, several orders of magnitude smaller than them, so the calculations in the study are completely negligible).The mass of protons or neutrons is the same for all atoms, and the masses of protons and neutrons themselves are not very different. So why would the relative atomic mass be the number of neutrons + the number of protons.

The criterion for relative atomic mass is 12C atoms, which have protons, neutrons, and electrons within them.

The mass of electrons is much smaller than that of protons, neutrons and is negligible.

There are 12 protons, 6 neutrons in the 6c atom.

Protons and neutrons have similar masses and are approximately equal.

The relative masses of both protons and neutrons can be deduced to be 1

So: relative atomic mass = number of protons * relative mass of protons + number of neutrons * relative mass of neutrons.

Number of neutrons * 1 + number of protons * 1

Number of neutrons + number of protons.

Because the factor that determines the mass of an atom is the nucleus, which in turn is made up of protons + neutrons.

Because the mass of the electron is very small, the relative atomic mass is the mass of the atom, and the mass of the atom is mainly concentrated in the nucleus, so it is equal to the mass of the proton + the mass of the neutron, and now their mass can be regarded as 1, so there are as many protons and neutrons, and the mass of protons and neutrons is as large.

Number of protons = number of nuclear charges = number of electrons outside the nucleus = number of atomic numbers.

Number of protons + number of neutrons relative to atomic mass.

1. The number of protons determines the nucleus.

The number of charges carried (number of nuclear charges).

Because the number of protons in the atom = the number of nuclear charges.

2. The number of protons determines the type of element.

3. The number of protons and neutrons determines the relative atomic mass of the atom.

Because the number of protons in the atom + the number of neutrons = the relative atomic mass of the atom.

Number of protons = number of nuclear charges = number of electrons outside the nucleus = number of atomic numbers. Number of protons + number of neutrons relative to atomic mass.

1. The number of protons determines the number of charges carried by the nucleus (the number of nuclear charges) because the number of protons in the atom = the number of nuclear charges.

2. The number of protons determines the type of element.

3. The number of protons and neutrons determines the relative atomic mass of the atom.

Because the number of protons in the atom + the number of neutrons = the relative atomic mass of the atom.

Pro, because the atomic mass of the number of protons * the mass of a proton + the number of neutrons * the mass of a neutron + the number of electrons * the mass of an electron.

Since the mass of electrons is too small to be negligible, the atomic mass of the number of protons * the mass of one proton + the number of neutrons * the mass of one neutron.

One of the criteria for finding the relative atomic mass is 1 12 of the atomic mass of carbon

Both sides are divided by this criterion at the same time, while the mass of a proton is divided by criterion 1, and the mass of a neutron is divided by criterion 1, so.

Relative atomic mass Number of protons + number of neutrons.

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Atomic weight = number of protons * relative mass of protons + number of neutrons * relative mass of neutrons + number of electrons * relative mass of electrons.

The approximation can be said in this way, but in fact there is an error.

The rest mass of the proton is.

The rest mass of the neutron is.

The relative mass of the two is approximately equal to 1

The mass of electrons is usually omitted because it is too small compared to protons and neutrons.

So approximately.

Atomic weight, number of protons, number of neutrons.

And because the number of protons = atomic number.

So approximately.

Atomic Weight, atomic number, and neutron number.

Because the mass of electrons is much smaller than that of protons, neutrons and is negligible. The masses of protons and neutrons are similar, and the relative "atomic" masses of protons containing modulus and neutrons are close to 1 (respectively008), so the relative atomic mass of the atom can be considered as the number of protons and the number of neutrons.

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Analysis: It is known that the mass of a proton and a neutron is approximately equal to 1 12 of the mass of a carbon-12 atom, while the mass of an electron is only 1 1836 of the mass of a traveling bridge protonTry to pass the calculation instructions:

The relative atomic mass is approximately equal to the number of protons plus the number of neutrons.

Same as above: It can be deduced that the relative mass of a proton and a neutron is approximately equal to that of a macrodrom of about 1 Since: the mass of an electron is only equivalent to 1 1836 of the mass of a proton, which is negligible.

The mass of the atom is about = the mass of the proton + the mass of the seed.

Then: The relative atomic mass is approximately equal to the number of protons plus the number of neutrons.

The mass of electrons is very small and negligible compared to protons and neutrons, so the mass of atoms is mainly concentrated in protons and neutrons.

And the mass of protons and neutrons is very similar, so they can be considered to have equal mass, so they add up to the mass of an atom, and then compare it with the mass of C-12 1 12, which is the number of protons + the number of neutrons, that is, the relative atomic mass.

Analysis: 1An atom is made up of a nucleus and extranuclear electrons, and the nucleus is made up of protons and neutrons.

2.The mass of electrons outside the nucleus is small and negligible, so the mass of the atom is concentrated on the nucleus.

3.The ratio of the atomic mass to the carbon-12 atomic mass of 1 12 is both relative to the atomic mass.

4.The number of protons is the ratio of the mass of the proton to the mass of the carbon-12 atom 1 12.

5.The number of neutrons is the ratio of the mass of the neutron to the mass of the carbon-12 atom 1 12.

6.Therefore, the relative atomic mass = the number of protons + the number of neutrons.

Number of nuclear charges = number of protons = number of electrons outside the nucleus; The number of nuclear charges is the number of positive charges carried by the nucleus, and each proton carries 1 unit of positive charge, so the number of protons is equal to the number of positive charges carried by protons; It is also equal to the number of positive charges carried by the nucleus; Therefore, there are: the number of nuclear charges = the number of protons, and furthermore, the charge carried by the nucleus is equal to the number of charges carried by the electrons outside the nucleus, and the number of electrons is also equal to the number of negative charges carried by the electrons, so there is: the number of nuclear charges = the number of protons = the number of electrons outside the nucleus relative to the atomic mass The number of protons + the number of neutrons Atomic mass = the mass of protons + the mass of neutrons + the mass of electrons, because the mass of electrons is small and negligible, so there is:

Atomic mass Proton mass + neutron mass = mass of each proton * number of protons + mass of each neutron * number of neutrons divided by 1 12 of the mass of carbon atoms at the same time, we get: relative atomic mass number of protons + number of neutrons.