Textbook Question
Discussing this chapter, a classmate says, 'Since elements that form cations are metals and elements that form anions are nonmetals, elements that do not form ions are metalloids.' Do you agree or disagree?
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Ch.7 - Periodic Properties of the Elements
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232
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Table of contents
- Ch.1 - Introduction: Matter, Energy, and Measurement177
- Ch.2 - Atoms, Molecules, and Ions231
- Ch.3 - Chemical Reactions and Reaction Stoichiometry216
- Ch.4 - Reactions in Aqueous Solution189
- Ch.5 - Thermochemistry175
- Ch.6 - Electronic Structure of Atoms168
- Ch.7 - Periodic Properties of the Elements150
- Ch.8 - Basic Concepts of Chemical Bonding177
- Ch.9 - Molecular Geometry and Bonding Theories200
- Ch.10 - Gases179
- Ch.11 - Liquids and Intermolecular Forces113
- Ch.12 - Solids and Modern Materials154
- Ch.13 - Properties of Solutions157
- Ch.14 - Chemical Kinetics199
- Ch.15 - Chemical Equilibrium128
- Ch.16 - Acid-Base Equilibria164
- Ch.17 - Additional Aspects of Aqueous Equilibria163
- Ch.18 - Chemistry of the Environment105
- Ch.19 - Chemical Thermodynamics164
- Ch.20 - Electrochemistry171
- Ch.21 - Nuclear Chemistry122
- Ch.22 - Chemistry of the Nonmetals82
- Ch.23 - Transition Metals and Coordination Chemistry79
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry16
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Not the one you use?Change textbook
Chapter 7, Problem 55
(a) Does metallic character increase, decrease, or remain unchanged as one goes from left to right across a row of the periodic table? (b) Does metallic character increase, decrease, or remain unchanged as one goes down a column of the periodic table?
Verified step by step guidance1
Step 1: Understand the concept of metallic character. Metallic character refers to the tendency of an element to lose electrons and form positive ions (cations). Elements with high metallic character are typically good conductors of electricity and heat, have a shiny appearance, and are malleable and ductile.
Step 2: Analyze the trend across a period (row) in the periodic table. As you move from left to right across a period, elements generally become less metallic. This is because the number of protons in the nucleus increases, which leads to a stronger attraction between the nucleus and the electrons, making it harder for the atoms to lose electrons.
Step 3: Analyze the trend down a group (column) in the periodic table. As you move down a group, the metallic character generally increases. This is because the atomic size increases, and the outer electrons are further from the nucleus, which reduces the effective nuclear charge experienced by these electrons, making it easier for the atoms to lose electrons.
Step 4: Relate these trends to specific examples. For instance, in the second period, lithium (Li) is more metallic than beryllium (Be), and in the alkali metal group, lithium (Li) is less metallic than cesium (Cs).
Step 5: Summarize the trends. Across a period, metallic character decreases from left to right. Down a group, metallic character increases. These trends are due to changes in atomic size and effective nuclear charge.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Metallic Character
Metallic character refers to the set of properties typically associated with metals, including conductivity, malleability, ductility, and luster. Elements with high metallic character tend to lose electrons easily, forming positive ions. This property is influenced by an element's position in the periodic table, which affects its atomic structure and behavior.
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Metallic Character Example
Periodic Trends
Periodic trends are predictable patterns observed in the periodic table, such as atomic radius, ionization energy, and electronegativity. As one moves from left to right across a period, elements generally become less metallic due to increasing nuclear charge, which attracts electrons more strongly. Conversely, moving down a group, atomic size increases, often leading to a greater metallic character.
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Effective Nuclear Charge
Effective nuclear charge (Z_eff) is the net positive charge experienced by an electron in a multi-electron atom. It accounts for the shielding effect of inner electrons, which reduces the full nuclear charge felt by outer electrons. As Z_eff increases across a period, the attraction between the nucleus and valence electrons strengthens, leading to a decrease in metallic character.
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Related Practice
Textbook Question
Consider the following equation:Al3+1g2 + e-¡Al2+1g2Which of the following statements are true? (i) The energychange for this process is the second electron affinity of Alatom since Al2+1g2 is formed. (ii) The energy change for thisprocess is the negative of the third ionization energy of the Alatom. (iii) The energy change for this process is the electronaffinity of the Al2+ ion.