Electron Configurations, Box diagrams, and Noble gas notation

How many unpaired electrons are present in a nitrogen atom?

• 1

• 2

• 3

• 4

Answer explanation

A nitrogen atom has 7 electrons. Its electron configuration is 1s² 2s² 2p³. The 2p subshell has 3 electrons, each occupying separate orbitals, resulting in 3 unpaired electrons.

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Which of the following elements has the same number of unpaired electrons as oxygen?

• Carbon

• Sulfur

• Neon

• Fluorine

Answer explanation

Oxygen has 2 unpaired electrons. Sulfur, being in the same group as oxygen, also has 2 unpaired electrons in its outer shell, while carbon has 2, neon has none, and fluorine has 1. Thus, sulfur is the correct choice.

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• 0

• 1

• 2

• 3

Answer explanation

The electron configuration 1s² 2s² 2p⁴ indicates that the 2p subshell has 4 electrons. In the 2p subshell, there are 3 orbitals, and with 4 electrons, 2 will be paired and 2 will remain unpaired. Thus, there are 2 unpaired electrons.

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Explain why the number of unpaired electrons in an iron atom is important for its magnetic properties.

• Unpaired electrons do not affect magnetism.

• Unpaired electrons create a magnetic field that contributes to magnetism.

• Paired electrons are responsible for magnetism.

• The number of unpaired electrons determines the color of the atom.

Answer explanation

Unpaired electrons create a magnetic field due to their spin, which contributes to the overall magnetism of an atom. In iron, the presence of unpaired electrons is crucial for its ferromagnetic properties.

• 0

• 1

• 4

• 6

Answer explanation

A chromium atom has the electron configuration [Ar] 3d^5 4s^1. The 3d subshell has 5 electrons, all unpaired, and the 4s subshell has 1 unpaired electron, totaling 6 unpaired electrons.

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What is the complete configuration for Sulfur?

• 1s² 2s² 2p⁶ 3s⁶

• 1s² 2s² 2p⁶ 3s² 3p⁵

• 1s² 2s² 2p⁶ 3s² 3p⁴

• 1s² 2s² 2p⁶ 3s² d⁴

Answer explanation

The complete electron configuration for Sulfur (atomic number 16) is 1s² 2s² 2p⁶ 3s² 3p⁴, indicating it has 2 electrons in the 1s, 2 in the 2s, 6 in the 2p, 2 in the 3s, and 4 in the 3p subshell.

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What element is this the noble gas notation for?

[Ar]4s² 3d¹

• Yttrium

• Scandium

• Calcium

• Strontium

Answer explanation

The noble gas notation [Ar]4s² 3d¹ corresponds to the electron configuration of Scandium, which has an atomic number of 21. Yttrium, Calcium, and Strontium have different configurations, confirming Scandium as the correct answer.

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Which element has this ground state configuration?

Answer explanation

The ground state electron configuration for Indium (In) is [Kr] 4d10 5s2 5p1. This matches the given configuration, confirming that Indium is the correct answer.

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What element does this box diagram represent?

Answer explanation

The box diagram represents Zirconium, which is identified by its atomic number 40 and symbol Zr. This element is known for its high resistance to corrosion and is used in various applications, including nuclear reactors.

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How many valence electrons does this configuration have? 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

• 0

• 6

• 8

• 18

Answer explanation

The configuration shows 4s and 4p orbitals filled with 2 and 6 electrons, respectively. The valence electrons are those in the outermost shell (n=4), totaling 8 (2 from 4s and 6 from 4p). Thus, the answer is 8.

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