Unit 3 Review: Electron Models and Trends

Ionization energy is...

• The energy needed to remove an electron from an atom

• The ability of an atom to attract shared electrons

• The distance between the nucleus and the valence electrons

• The tendency of an atom to do chemical reactions

Answer explanation

Ionization energy refers to the energy required to remove an electron from an atom, making the first answer choice correct. The other options describe different atomic properties, not ionization energy.

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What factor contributes to increased atomic radius as you move down a group.

• More protons in the nucleus

• Additional Energy Levels

• Additional Neutrons

• Decrease in number of electrons

Answer explanation

As you move down a group in the periodic table, additional energy levels are added, which increases the distance between the nucleus and the outermost electrons, resulting in a larger atomic radius.

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Which of the following elements has the lowest ionization energy?

• Fluorine

• Phosphorous

• Rubidium

• Lithium

Answer explanation

Rubidium has the lowest ionization energy among the given elements because it is located in Group 1 of the periodic table, where elements have larger atomic radii and lower ionization energies compared to nonmetals like fluorine.

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Which element would be the most reactive?

• Li

• K

• Rb

• Fr

Answer explanation

Fr (francium) is the most reactive alkali metal due to its position in Group 1 of the periodic table. As you move down the group, reactivity increases, making Fr more reactive than Li, K, and Rb.

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From the following elements, which has the highest electronegativity?

• Cl

• F

• Br

• I

Answer explanation

Fluorine (F) has the highest electronegativity of all elements, rated at 3.98 on the Pauling scale. Chlorine (Cl), bromine (Br), and iodine (I) have lower values, making F the most electronegative element.

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Which group is incorrectly named?

• Group 2: Alkali Metals

• Group 18: Noble Gases

• Group 17: Halogens

• Group 13: Boron Family

Answer explanation

Group 2 is incorrectly named as Alkali Metals; it should be Alkaline Earth Metals. Alkali Metals are actually in Group 1, while Group 2 contains elements like magnesium and calcium.

Tags

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What is the electron configuration for Arsenic?

• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4p³

• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p³

• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 4d¹⁰ 4p³

Answer explanation

The electron configuration for Arsenic (atomic number 33) is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p³. This configuration fills the 3d subshell before the 4p subshell, making the correct choice the third option.

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Which element has a noble gas configuration of [Ne] 3s² 3p³?

• Magnesium

• Phosphorus

• Aluminum

• Sulfur

Answer explanation

The noble gas configuration [Ne] 3s² 3p³ corresponds to phosphorus, which has 15 electrons. Magnesium (12), aluminum (13), and sulfur (16) do not match this configuration.

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This Lewis dot structure for Oxygen is accurate

• True

• False

Answer explanation

The Lewis dot structure for oxygen typically shows six valence electrons, with two lone pairs and two bonding pairs. If the provided structure does not reflect this, then it is inaccurate, making the statement false.

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What is this element? 
1s²2s²2p⁶3s²3p⁶
4s²3d¹⁰4p⁶

• Argon

• Krypton

• Selenium

• Bromide

Answer explanation

The electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ corresponds to Krypton, which has 36 electrons. It is a noble gas, and the configuration shows a complete outer shell, characteristic of noble gases.

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