Question #55758

1. According to the Heisenberg Uncertainty Principle, it is impossible to know precisely both
the ____________ and the ________ of an electron.
2. Write all possible magnetic quantum number of an electron in a 5d subshell.
3. Circle the quantum numbers must be the same for the orbitals that they designate to be
degenerate (same energy level) in a;
a) many-electron system n, l, ml, ms
b) one electron system (hydrogen) n, l, ml, ms
4. All of the subshells in a given shell have the same energy in the hydrogen atom. In a manyelectron atom, the subshells in a given shell do not have the same energy. Why?

Expert's answer

1. According to the Heisenberg Uncertainty Principle, it is impossible to know precisely both

the position and the momentum of an electron.

2. All possible magnetic quantum number of an electron in a 5d subshell: –2, –1, 0, +1, +2.

3. Circle the quantum numbers must be the same for the orbitals that they designate to be

degenerate (same energy level) in a;

b) one electron system (hydrogen) n, l, ml, ms.

4. Answer: Because of the Pauli principle.

The Pauli exclusion principle is the quantum mechanical principle that states that two identical fermions (particles with half-integer spin) cannot occupy the same quantum state simultaneously. In the case of electrons.

It can be stated as follows:

• it is impossible for two electrons of a poly-electron atom to have the same values of the four quantum numbers (n, l, ml and ms);

• for two electrons residing in the sameorbital, n, l, and ml are the same, so ms must be different and the electrons have opposite spins.

the position and the momentum of an electron.

2. All possible magnetic quantum number of an electron in a 5d subshell: –2, –1, 0, +1, +2.

3. Circle the quantum numbers must be the same for the orbitals that they designate to be

degenerate (same energy level) in a;

b) one electron system (hydrogen) n, l, ml, ms.

4. Answer: Because of the Pauli principle.

The Pauli exclusion principle is the quantum mechanical principle that states that two identical fermions (particles with half-integer spin) cannot occupy the same quantum state simultaneously. In the case of electrons.

It can be stated as follows:

• it is impossible for two electrons of a poly-electron atom to have the same values of the four quantum numbers (n, l, ml and ms);

• for two electrons residing in the sameorbital, n, l, and ml are the same, so ms must be different and the electrons have opposite spins.

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