Electron Configuration and Quantum Numbers

The correct set of four quantum numbers for the balance electron of rubidium atom

(z=37) is

• 5, 1, 1, +1/2

• 6, 0, 0, +1/2

• 5, 0, 0, +1/2

• 5, 1, 0, -1/2

Answer explanation

The valence electron of rubidium (Z=37) is in the 5th energy level (n=5), with an angular momentum quantum number (l=0) indicating an s orbital. The spin quantum number can be +1/2, making the correct set 5, 0, 0, +1/2.

Tags

NGSS.HS-PS1-1

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What is the maximum number of electrons that can occupy a single d orbital?

• 2

• 6

• 10

• 14

Answer explanation

A single d orbital can hold a maximum of 2 electrons, as per the Pauli exclusion principle, which states that no two electrons can have the same set of quantum numbers.

Which of the following quantum numbers describes the size of the electron cloud?

• Principal quantum number

• Azimuthal quantum number

• Magnetic quantum number

• Spin quantum number

Answer explanation

The principal quantum number describes the size of the electron cloud, indicating the energy level and distance of the electron from the nucleus. Higher values correspond to larger electron clouds.

Which of the following elements has the electron configuration [Ne] 3s² 3p⁵?

• Chlorine

• Argon

• Sulfur

• Phosphorus

Answer explanation

The electron configuration [Ne] 3s² 3p⁵ corresponds to chlorine (Cl), which has 17 electrons. Chlorine is in period 3 and group 17 of the periodic table, confirming it has this specific configuration.

Tags

NGSS.HS-PS1-1

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What is the maximum number of electrons that can occupy a single orbital?

• 1

• 2

• 3

• 4

Answer explanation

A single orbital can hold a maximum of 2 electrons due to the Pauli exclusion principle, which states that no two electrons can have the same set of quantum numbers. Therefore, the correct answer is 2.

What is the principal quantum number for the outermost electron in a calcium atom?

• 2

• 3

• 4

• 5

Answer explanation

Calcium has an atomic number of 20, with the electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s². The outermost electrons are in the 4s subshell, making the principal quantum number for the outermost electron 4.

Tags

NGSS.HS-PS1-1

Which of the following elements has an electron configuration that ends in 4s^1?

• potassium

• calcium

• scandium

• titanium

Answer explanation

Potassium (K) has an electron configuration of 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1, ending in 4s^1. Calcium (Ca) ends in 4s^2, scandium (Sc) ends in 3d^1 4s^2, and titanium (Ti) ends in 3d^2 4s^2.

Tags

NGSS.HS-PS1-1

This orbital diagram represents:  

• C

• B

• N

• O

Answer explanation

The orbital diagram shows the electron configuration for element C (Carbon), which has 6 electrons. The arrangement of electrons in the diagram confirms it corresponds to Carbon's atomic structure.

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NGSS.HS-PS1-1

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Label the three parts of an electron configuration:

d

e

f

electrons

protons

group

period (row)

section

family

block (orbital)

What is the shape of the p orbitals in an atom?

• a sphere.

• a dumbbell.

• a torus.

• a cube.

Answer explanation

The shape of p orbitals is described as a dumbbell. This shape arises from the angular momentum of the electrons, which creates two lobes on either side of the nucleus, distinguishing them from s orbitals that are spherical.