How many electrons in an atom could have these sets of quantum numbers?

n=3
n=5 , l=2
n=7 , l=3 , ml=-1

To determine the number of electrons that can have a given set of quantum numbers, we need to follow a few rules:

1. The principal quantum number (n) indicates the energy level or shell of an electron. For a given energy level, the maximum number of electrons it can hold is given by the formula 2n^2. Therefore, for n=3, the maximum number of electrons is 2(3)^2 = 18.

2. The azimuthal quantum number (l) determines the subshell or orbital type. It can have values ranging from 0 to n-1. The number of orbitals within a subshell is given by the formula 2l + 1. So, for the set of quantum numbers n=5, l=2, the number of orbitals is 2(2) + 1 = 5.

3. The magnetic quantum number (ml) specifies the orientation of the orbital and can have values ranging from -l to +l. The number of electrons that can have a specific combination of n, l, and ml is 2.

Now, let's consider the given sets of quantum numbers:

1. n=3: In this case, the maximum number of electrons is 2(3)^2 = 18.

2. n=5, l=2: Here, the number of orbitals is 2(2) + 1 = 5. Each orbital can hold 2 electrons. So, the total number of electrons that can have this set of quantum numbers is 5(2) = 10.

3. n=7, l=3, ml=-1: For this set of quantum numbers, there is only one orbital since ml = -1. Therefore, the number of electrons that can have these quantum numbers is 2.

To summarize:
- For n=3, the number of electrons is 18.
- For n=5, l=2, the number of electrons is 10.
- For n=7, l=3, ml=-1, the number of electrons is 2.

To determine the number of electrons in an atom with given sets of quantum numbers, we need to use the principle that the maximum number of electrons in a specific energy level (n) is given by 2n².

1. For the quantum numbers n = 3:
The maximum number of electrons in the third energy level (n = 3) is calculated as:
2n² = 2 * (3)² = 2 * 9 = 18 electrons.

2. For the quantum numbers n = 5 and l = 2:
The maximum number of electrons in the fifth energy level (n = 5) with an l value of 2 is given by:
2n² = 2 * (5)² = 2 * 25 = 50 electrons.

3. For the quantum numbers n = 7, l = 3, and ml = -1:
The maximum number of electrons in the seventh energy level (n = 7) with an l value of 3 and an ml value of -1 is calculated as:
2n² = 2 * (7)² = 2 * 49 = 98 electrons.

Therefore, the number of electrons in an atom with the given quantum numbers are:
1. n = 3: Maximum 18 electrons.
2. n = 5, l = 2: Maximum 50 electrons.
3. n = 7, l = 3, ml = -1: Maximum 98 electrons.