# Quiz 3 - Quantum Theory & Atomic Structure | Quantum Theory and Atomic Structure

1

Which quantum number determines the shape of an orbital?

The angular momentum quantum number (l) determines the shape of an atomic orbital within a given electron shell, and it dictates the allowable values for the magnetic quantum number (ml).

2

What does an electron in an excited state signify compared to a ground state?

An excited state occurs when an electron has absorbed energy and moved to a higher energy subshell or orbital, which is an energy level above the ground state.

3

Which principle explains why two electrons in the same orbital must have opposite spins?

The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of four quantum numbers; therefore, electrons in the same orbital must have opposite spins.

4

When writing the electron configuration of Fe (Z=26), which of the following denotes the correct order of filling orbitals?

The correct order of filling orbitals is 1s 2s 2p 3s 3p 4s 3d, according to the Aufbau principle. This principle describes the sequential filling of orbitals in increasing order of energy.

5

How does the quantum mechanical model of the atom differ from Bohr's model?

The quantum mechanical model of the atom differs from Bohr's model by not allowing electrons to reside in discrete orbits but instead as probabilities in atomic orbitals, representing wave-like behavior.

6

Which set of quantum numbers is not possible for an electron?

The set n=1, l=1, ml=0, ms=+1/2 is not possible because the angular momentum quantum number (l) must be in the range 0 to n-1. For n=1, l can only be 0.

7

According to Hund's Rule, how would electrons be distributed among three degenerate p orbitals in a nitrogen atom?

Hund's Rule states that electrons will occupy degenerate orbitals singly and with parallel spins to maximize total spin before pairing up. Therefore, nitrogen with 3 p electrons would have one in each orbital, all with the same spin.

8

What is the maximum number of electrons that can occupy a single orbital, according to the Pauli exclusion principle?

The Pauli exclusion principle states that each orbital can accommodate a maximum of 2 electrons, each with opposite spins.

9

What is the maximum number of electrons that can occupy the d subshell?

The d subshell can contain a maximum of 5 orbitals, and with each orbital capable of holding 2 electrons, the d subshell can hold a total of 10 electrons.

10

What does the principle of electron spin describe?

The principle of electron spin describes a fundamental property of electrons, akin to an intrinsic angular momentum, which can be observed as two distinct states represented by quantum spin numbers +1/2 and -1/2.