Chapter 4: Problem 18
Locate each group of elements on the periodic table and list its group number. (a) alkali metals (b) alkaline earth metals (c) halogens (d) noble gases
Short Answer
Expert verified
The group numbers for the elements are: (a) alkali metals - Group 1, (b) alkaline earth metals - Group 2, (c) halogens - Group 17, (d) noble gases - Group 18.
Step by step solution
01
Identifying Alkali Metals
The alkali metals are located in group 1 of the periodic table. This group includes elements like lithium (Li), sodium (Na), and potassium (K). They are characterized by having one valence electron, which they tend to lose to form cations with a charge of +1.
02
Identifying Alkaline Earth Metals
Alkaline earth metals are found in group 2 of the periodic table. Elements such as beryllium (Be), magnesium (Mg), and calcium (Ca) belong to this group. These elements have two valence electrons and typically form cations with a charge of +2.
03
Locating Halogens
Halogens are located in group 17 of the periodic table. This group contains fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Halogens have seven valence electrons and usually form anions with a charge of -1.
04
Finding Noble Gases
Noble gases are found in group 18 of the periodic table. They include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). These elements have a full valence shell and are mostly non-reactive.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Alkali Metals
The alkali metals form the first group of the periodic table, which includes familiar elements like lithium (Li), sodium (Na), and potassium (K). Notorious for their reactivity, these metals have just one valence electron that they are keen to give up, forming cations with a +1 charge.
What makes alkali metals so special? Their eagerness to lose that single outer electron leads to some spectacular chemical reactions, typically with water or halogens. They are also characterized by their softness, low densities, and excellent conductivity of heat and electricity. However, due to their high reactivity, you won't stumble upon them in nature in their pure form; they're always bonded with other elements.
Understanding the properties of alkali metals is crucial for students as it lays the groundwork for grasping concepts in chemical bonding, reactivity trends, and electron configurations. By observing their group 1 position, it becomes clear why alkali metals act as they do, following the periodic trends.
What makes alkali metals so special? Their eagerness to lose that single outer electron leads to some spectacular chemical reactions, typically with water or halogens. They are also characterized by their softness, low densities, and excellent conductivity of heat and electricity. However, due to their high reactivity, you won't stumble upon them in nature in their pure form; they're always bonded with other elements.
Understanding the properties of alkali metals is crucial for students as it lays the groundwork for grasping concepts in chemical bonding, reactivity trends, and electron configurations. By observing their group 1 position, it becomes clear why alkali metals act as they do, following the periodic trends.
Alkaline Earth Metals
Step right next to the alkali metals on the periodic table, and you'll meet their neighbors, the alkaline earth metals, making up group 2. This group is home to elements such as beryllium (Be), magnesium (Mg), and calcium (Ca). With two valence electrons, these elements are slightly less reactive than their group 1 companions and form cations with a +2 charge after losing their valence electrons.
The importance of alkaline earth metals stretches from our skeletal system, courtesy of calcium, to aerospace engineering with the use of lightweight beryllium. They share some common traits: they are silvery, relatively soft metals and serve as good conductors of electricity. Also common for this group is their occurrence in earth's crust but not in their free elemental state.
Their position in group 2 enables us to predict their behavior in reactions and their role in stabilizing ionic compounds. Students often find it helpful to compare the alkaline earth metals with the alkali metals to deepen their understanding of group trends in the periodic table.
The importance of alkaline earth metals stretches from our skeletal system, courtesy of calcium, to aerospace engineering with the use of lightweight beryllium. They share some common traits: they are silvery, relatively soft metals and serve as good conductors of electricity. Also common for this group is their occurrence in earth's crust but not in their free elemental state.
Their position in group 2 enables us to predict their behavior in reactions and their role in stabilizing ionic compounds. Students often find it helpful to compare the alkaline earth metals with the alkali metals to deepen their understanding of group trends in the periodic table.
Halogens
Take a quantum leap across the periodic table to group 17, and find the halogens, the highly reactive nonmetals comprising elements like fluorine (F) and chlorine (Cl). A unique feature is their seven valence electrons, making them just one electron shy of a full octet ― a driving force behind their high reactivity.
What makes halogens so pivotal in chemistry? From household bleach containing chlorine to the fluorine in toothpaste, halogens are everywhere in everyday life. Their behaviors are diverse: they can be corrosive, poisonous, or even lifesaving as disinfectants. Another interesting trait is their state of matter at room temperature, spanning from gases (like fluorine and chlorine) to liquids (like bromine) and solids (like iodine and astatine).
Their tendency to gain that one elusive electron results in the formation of anions with a -1 charge. When students understand the halogens' location in group 17, it paves the way for deeper insights into topics such as electronegativity, interhalogen compounds, and the role of halogens in organic chemistry.
What makes halogens so pivotal in chemistry? From household bleach containing chlorine to the fluorine in toothpaste, halogens are everywhere in everyday life. Their behaviors are diverse: they can be corrosive, poisonous, or even lifesaving as disinfectants. Another interesting trait is their state of matter at room temperature, spanning from gases (like fluorine and chlorine) to liquids (like bromine) and solids (like iodine and astatine).
Their tendency to gain that one elusive electron results in the formation of anions with a -1 charge. When students understand the halogens' location in group 17, it paves the way for deeper insights into topics such as electronegativity, interhalogen compounds, and the role of halogens in organic chemistry.
Noble Gases
Finally, at the far right edge of the periodic table lies the serene kingdom of the noble gases, occupying group 18. This prestigious club includes helium (He), neon (Ne), and argon (Ar) among others. Their claim to fame? A complete valence shell rendering them famously unreactive and colorless, earning their moniker of 'inert' or 'noble' gases.
The noble gases' lack of reactivity makes them perfect candidates in applications where non-reactivity is key. Think helium-filled balloons floating upwards, or the neon lights illuminating cityscapes with vibrant colors. Even the protective environment for welding is courtesy of argon. Despite their inertness, under extreme conditions, xenon and krypton can form compounds, which are a subject of interest in high-pressure chemistry.
Understanding noble gases and their complete octet provides a foundation for discussing electron configurations and stability in chemical bonding. Their presence in group 18 is a testament to the elegance of the periodic trends and helps students grasp the significance of a full valence shell. Their stable nature is an excellent climax to the lesson, showing the contrast between the highly reactive groups and these composed elemental dignitaries.
The noble gases' lack of reactivity makes them perfect candidates in applications where non-reactivity is key. Think helium-filled balloons floating upwards, or the neon lights illuminating cityscapes with vibrant colors. Even the protective environment for welding is courtesy of argon. Despite their inertness, under extreme conditions, xenon and krypton can form compounds, which are a subject of interest in high-pressure chemistry.
Understanding noble gases and their complete octet provides a foundation for discussing electron configurations and stability in chemical bonding. Their presence in group 18 is a testament to the elegance of the periodic trends and helps students grasp the significance of a full valence shell. Their stable nature is an excellent climax to the lesson, showing the contrast between the highly reactive groups and these composed elemental dignitaries.
