Question

Explain the significance of three Quantum numbers in predicting the positions of an electron inan atom.

Answer 1

Answer:

In chemistry there are 4 quantum umbers n, l , m and s .

they are used to show the position of an electron in an atom .

1. the first one is n that is principal quantum number .

This describes the electron shell, or energy level, of an electron.

2. The second one is l which is azimuthal quantum number.

The value of l ranges from 0 to n − 1, so the first p orbital (l = 1) appears in the second electron shell (n = 2), the first d orbital (l= 2) appears in the third shell (n = 3), and so on.

l = 0, 1, 2,..., n − 1

3. The third one is magnetic quantum number which is represented by m.

This describes the specific orbital within that subshell, and yields the projection of the orbital angular momentum along a specified axis.

4.And the fourth one is spin quantum number which is represented by S .

The value of s is -1 or +1 .

Answer 2

Answer:

:

Each electron in an atom is described by a set of three quantum numbers n,l and ml.

1. Principal quantum number (n) : The principal quantum number is used to describe the size and energy of the main shell. It is denoted by 'n'. 'n' has positive integer values of 1,2,3,............. It is used to know the number of orbitals (n2) and electrons in an orbit. (2n2).

As 'n' increases the shells becomes larger and the electrons in those shells are farther from the nucleus and their energies increases.

2. The angular-momentum quantum number(l) : 'l' has integer values from '0' to n-1, for each value of 'n'. Each 'l' value represents one sub-shell. It is used to describe the shape of an orbit.

3. The magnetic quantum number (ml) : The magnetic quantum number (ml) has integer values between -l and +l including zero.

If l=0, the possible ml value is 1. l=1 , the possible ml value is -1, 0 and 1.

Thus for a certain value of l, there are (2l+1) integer values of ml.

These values describe the orientation of the orbital in space relative to the other orbitals in the atom.

Ex : When l=1,(2l+1)=3, that means ml has 3 values namely -1,0,1 or three p orbitals, with different orientations along x,y,z axes, labelled as px,py and pz orbitals.

Predicting the position of an electron in an atom : If the values of n,l and ml are 2,1,-1 respectively the electron is present in 2px orbital in L - shell.

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Explanation: