(b) How many electrons must a sulfur atom gain to achieve an octet in its valence shell? (c) If an atom has the electron configuration 1s2 2s2 2p3, how many electrons must it gain to achieve an octet?

Name: Chemistry: The Central Science
Author: Brown
ISBN: 9780134414232

Verified step by step guidance

Step 1: Understand the concept of an octet. An octet refers to having eight electrons in the valence shell, which is a stable electron configuration often seen in noble gases.

Step 2: For part (b), identify the electron configuration of a sulfur atom. Sulfur is in group 16 of the periodic table and has an atomic number of 16. Its electron configuration is:

{1s}^{2} {2s}^{2} {2p}^{6} {3s}^{2} {3p}^{4}

Step 3: Determine how many electrons sulfur needs to gain to achieve an octet in its valence shell. Sulfur's valence shell is the third shell, which currently has 6 electrons (3s² 3p⁴). To achieve an octet, it needs 8 electrons, so it must gain 2 electrons.

Step 4: For part (c), analyze the given electron configuration:

{1s}^{2} {2s}^{2} {2p}^{3}

. This configuration belongs to nitrogen, which is in group 15 of the periodic table.

Step 5: Calculate how many electrons nitrogen needs to gain to achieve an octet. The valence shell is the second shell, which currently has 5 electrons (2s² 2p³). To achieve an octet, it needs 8 electrons, so it must gain 3 electrons.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Octet Rule

The octet rule is a chemical principle stating that atoms tend to gain, lose, or share electrons to achieve a full outer shell of eight electrons, resembling the electron configuration of noble gases. This rule is fundamental in understanding the stability of atoms and their tendency to form bonds, as achieving an octet often leads to lower energy states and increased stability.

Valence Electrons

Valence electrons are the electrons in the outermost shell of an atom that are involved in chemical bonding. For sulfur, which has six valence electrons, gaining two additional electrons allows it to complete its octet. Understanding the number of valence electrons is crucial for predicting how an atom will interact with others in chemical reactions.

Electron Configuration

Electron configuration describes the distribution of electrons in an atom's orbitals, represented by a series of numbers and letters. For example, the configuration 1s2 2s2 2p3 indicates that the atom has five valence electrons in the second shell. Analyzing electron configurations helps determine how many electrons an atom needs to gain or lose to achieve a stable octet.

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Illustrated are four ions — A, B, X, and Y— showing their relative ionic radii. The ions shown in red carry positive charges: a 2+ charge for A and a 1+ charge for B. Ions shown in blue carry negative charges: a 1- charge for X and a 2- charge for Y. (b) Among the combinations in part (a), which leads to the ionic compound having the largest lattice energy?