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2 votes
The number that describes the main energy

level of an electron in an atom is
-------------------
1. the magnetic quantum number mℓ
2. the mass number A.
3. the angular momentum (or subsidiary)
quantum number ℓ.
4. the principal quantum number n.
5. the atomic number Z.

2 Answers

4 votes

Answer:principal quantum number

Step-by-step explanation:

User Meouw
by
8.2k points
7 votes

Answer: 4. the principal quantum number n.

Step-by-step explanation:

Magnetic Quantum Number : It describes the orientation of the orbitals. It is represented as
m_l. The value of this quantum number ranges from
(-l\text{ to }+l). When l = 2, the value of
m_l will be -2, -1, 0, +1, +2.

Mass number is defined as the sum of number of protons and neutrons that are present in an atom. It is represented by A.

Azimuthal or angular momentum Quantum Number : It describes the shape of the orbital. It is represented as 'l'. The value of l ranges from 0 to (n-1). For l = 0,1,2,3... the orbitals are s, p, d, f...

Principle Quantum Number : It describes the size of the orbital and the main energy level of an electron in an atom. It is represented by n. Where, n = 1,2,3,4....

Atomic number is defined as the number of protons or number of electrons that are present in an atom. It is represented by Z.

User Nikita Skrebets
by
7.9k points
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