# Number of protons and neutrons per shell?

• the riddick25
In summary, there is a statement in the shell model of the nucleus that states there can only be two neutrons and two protons at each energy level, as they are both fermions. However, another source mentions that there can only be a maximum of two fermions at each energy level, regardless of whether they are neutrons or protons. The correct answer is that there can only be two fermions at each energy level, with unique quantum numbers for each.

#### the riddick25

before i start i wanted to make it clear that this is NOT homework. its just a quick question which puzzled me and my friend

In the shell model of the nucleus. i found a statement that said that since both neutrons and protons are fermions, there are restricted to 2 of each at each energy level.
but when reading something else, it said there could only be 2 at each energy level (not 2 of each)

so could someone please tell me the correct answer, are there 2 protons and 2 neutrons per shell (making 4), or just a total of 2.

thanks :)

neutron and proton are distinguishable fermions

you must have missinterpreted, the real statement is max one indistinguishable fermion per quantum state. Every indistinguishable fermion must have an unique set of quantum numbers.

## 1. How do you determine the number of protons and neutrons in an atom?

The number of protons in an atom is equal to the atomic number, which can be found on the periodic table. The number of neutrons can be calculated by subtracting the atomic number from the mass number of the atom.

## 2. What is the significance of the number of protons and neutrons in an atom?

The number of protons in an atom determines its atomic number and therefore its identity as an element. The number of neutrons affects the stability of the atom and can determine its isotopic form.

## 3. How many protons and neutrons can each electron shell hold?

The first electron shell can hold up to 2 electrons, the second can hold up to 8, the third can hold up to 18, and the fourth can hold up to 32. However, the maximum number of electrons in each shell can vary depending on the element.

## 4. Can the number of protons and neutrons in an atom change?

The number of protons in an atom cannot change without changing the identity of the element. However, the number of neutrons can change, resulting in different isotopes of the same element.

## 5. How does the number of protons and neutrons affect the mass of an atom?

The mass of an atom is primarily determined by the number of protons and neutrons it contains. The mass number of an atom is equal to the sum of its protons and neutrons.

Replies
5
Views
601
Replies
11
Views
1K
Replies
1
Views
683
Replies
3
Views
1K
Replies
2
Views
2K
Replies
3
Views
1K
Replies
5
Views
2K
Replies
4
Views
2K
Replies
15
Views
2K
Replies
16
Views
960