Question

Explain, in terms of ionization energies, why the alkali and alkaline earth metals are not used to make coins or jewelry.

Short answer

Alkali and alkaline earth metals have low ionization energies, making them highly reactive. This reactivity leads to a lack of durability and resistance to corrosion, which are essential qualities for materials used in making coins and jewelry.

Step-by-step solution

Understanding Ionization Energy

Ionization energy is the amount of energy required to remove an electron from an atom or ion. The lower the ionization energy, the easier it is to remove an electron from an atom, thus leading to higher reactivity.

Understand the Properties of Alkali and Alkaline Earth Metals

Alkali metals (group 1 elements on the periodic table) and alkaline earth metals (group 2 elements on the periodic table) have relatively low ionization energies. This means they can easily lose an electron and are highly reactive.

Apply the Properties to the Context of Coins and Jewelry

Coins and jewelry need to be made of materials that are durable, resistant to corrosion, and able to maintain their appearance over time. The high reactivity of alkali and alkaline earth metals makes them unsuitable for these purposes, as they will react easily with other substances and degrade or tarnish.

Key concepts

Alkali Metals

Alkali metals are a fascinating group of elements found in Group 1 of the periodic table. This group includes lithium, sodium, potassium, rubidium, cesium, and francium. Known for their shiny appearance and soft texture, these metals are incredibly interesting due to their high reactivity. One major reason for this reactivity is their low ionization energies. This means it takes only a small amount of energy to remove the outermost electron, making these metals eager to participate in chemical reactions.

It's also important to point out that alkali metals have a single electron in their outermost shell. This lone electron is quite easily lost, allowing these metals to form positive ions very readily. Because of this, they react violently with water and air, which is why you’ll rarely find them as a standalone metal in nature.

• Soft and shiny
• Low ionization energy
• Highly reactive
• Not typically found as free metals

Ultimately, while their fascinating properties make them a key study subject in chemistry, their high reactivity means they are unsuitable for use in everyday items like coins and jewelry.

Alkaline Earth Metals

Alkaline earth metals reside in Group 2 of the periodic table and include beryllium, magnesium, calcium, strontium, barium, and radium. These metals are slightly less reactive than their neighbors, the alkali metals, but they still hold relatively low ionization energies, making them quite reactive compared to other elements.

These metals have two electrons in their outermost shell, which they are eager to lose in order to achieve a stable electron configuration like that of noble gases. This characteristic influences their tendency to form ionic compounds readily and participate in various chemical reactions. Similar to alkali metals, alkaline earth metals are typically not found in pure form in nature because of their reactivity.

• Less reactive than alkali metals but still reactive
• Possess two outer electrons
• Form ionic bonds easily
• Low ionization energy contributes to their reactivity

Because of their reactivity, using alkaline earth metals in coins or jewelry would result in corrosion and discoloration, which is why other more stable metals are preferred for these purposes.

Reactivity of Metals

When we talk about the reactivity of metals, we're essentially discussing how quickly and easily they engage in chemical reactions. This property is heavily influenced by their ionization energies. A lower ionization energy means that a metal atom can easily lose electrons, thus becoming more reactive.

Metals located on the left side of the periodic table, like the alkali and alkaline earth metals, demonstrate this characteristic vividly. Because they can readily lose electrons, their reactivity is high, making them prone to oxidation and corrosion. This is a key reason why chemists and manufacturers avoid using these metals for products that require durability, such as coins and jewelry.

• Low ionization energy leads to high reactivity
• Reactivity indicates tendency for oxidation and corrosion
• Essential consideration in material selection for durability

For jewelry and coins, where aesthetic longevity and resistance to atmospheric conditions are crucial, metals with low reactivity like gold, silver, and platinum are preferred. These have higher ionization energies, making them far less reactive and more durable.