Book cover for Chemistry

Chemistry

Catherine E. Housecroft, Edwin C. Constable

ISBN #9780273715450

4th Edition

995 Questions

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Summary
Learning Objectives
Key Concepts
Example Problems
Explanations
Common Mistakes

Summary

Chapter 20 delves into periodicity in the elements, emphasizing the significance of ground state electronic configurations and how they influence various physical and chemical properties such as melting/boiling points, atomization enthalpies, ionization energies, and radii. The chapter highlights the trends observed across periods and specific groups like 1 and 18, providing a framework to understand and predict elemental behavior based on their position in the periodic table.

Learning Objectives

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Key Concepts

CONCEPT

DEFINITION

Acyclic and cyclic alkanes

A discussion of both open?chain (acyclic) and ring (cyclic) saturated hydrocarbons, emphasizing their structural features, nomenclature, conformational behavior (including ring strain and conformation), and the processes used in their interconversion and synthesis.

Example Problems

Example 1

Identify the groups of the periodic table to which the elements with the following general ground state electronic configurations belong: (a) $n s^{2} n p^{4}$ (b) $n s^{1}$ (c) $n s^{2} n p^{6}$ (d) $n s^{2}$ (e) $n s^{2}(n-1) d^{10}$ (f) $n s^{2} n p^{1}$

Example 2

An element, $X,$ has the ground state electronic configuration $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{2} 3 d^{5}$ (a) How many valence electrons does $\mathrm{X}$ possess? (b) What is the atomic number of X? (c) To which block of elements does X belong? (d) To which group does X belong? (e) Is $X$ a metal, semi-metal or non-metal? (f) Write out the ground state electronic configuration of the element after $X$ in the periodic table.

Example 3

An element, $Z$, has the ground state electronic configuration $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{4}$(a) How many valence electrons does X possess? (b) What is the atomic number of X? (c) To which block of elements does X belong? (d) To which group does $X$ belong? (e) Is $X$ a metal, semi-metal or non-metal? (f) Write out the ground state electronic configuration of the clement after $X$ in the periodic table.

Example 4

An clement, E, has an outer ground state electronic configuration of $n s^{2} n p^{2}$ (a) How many valence electrons does $\mathrm{E}$ possess? (b) How many unpaired electrons does E possess in the ground state? (c) To which block of elements does E belong? (d) To which group does E belong? (e) Is E likely to be a metal, semi-metal or non-metal? (f) What will be the likely formula of the compound that E forms with hydrogen? (g) Write out the outer ground state electronic configuration of an element three places to the right of $E$ in the periodic table.

Example 5

In terms of electronic configurations, why is He unique among the group 18 elements?
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Step-by-Step Explanations

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Common Mistakes

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