Lithium

Definition

Lithium is a soft, silver-white alkali metal that is the lightest of all metals. It is highly reactive and must be stored in an inert atmosphere or oil to prevent it from reacting with air or water. Lithium's unique properties and position on the periodic table make it a key element in understanding periodic trends and the organization of elements.

5 Must Know Facts For Your Next Test

1. Lithium is the first element in Group 1 (the alkali metals) on the periodic table, making it the most electropositive and reactive of all metals.
2. Lithium has the smallest atomic radius of all the alkali metals due to its position at the top of the group.
3. As an alkali metal, lithium has a low ionization energy and readily loses its single valence electron to form a positive ion (Li+).
4. Lithium is the least dense solid element and has the highest specific heat capacity of any solid element.
5. Lithium compounds are used in a variety of applications, including batteries, ceramics, glass, and psychiatric medications.

Review Questions

• Explain how lithium's position on the periodic table relates to its physical and chemical properties.
  • As the first element in Group 1 (the alkali metals) on the periodic table, lithium has the smallest atomic radius and the highest electronegativity among the alkali metals. This is due to its position at the top of the group, where atomic radius increases and electronegativity decreases as you move down the group. These periodic trends directly influence lithium's high reactivity, low ionization energy, and ability to readily lose its single valence electron to form a positive ion (Li+).
• Describe how lithium's unique properties contribute to its diverse range of applications.
  • Lithium's low density, high specific heat capacity, and ability to form a variety of compounds make it useful in numerous applications. Its lightweight nature and high energy density make it ideal for use in batteries, while its ability to modify the properties of ceramics and glass makes it valuable in those industries. Additionally, lithium compounds have found use in psychiatric medications due to their ability to stabilize mood and treat conditions like bipolar disorder. The versatility of lithium is a direct result of its position on the periodic table and the resulting physical and chemical characteristics.
• Analyze how the periodic trends observed for lithium, such as atomic radius and electronegativity, can be used to predict and explain the element's behavior in chemical reactions and interactions.
  • Lithium's position at the top of Group 1 on the periodic table means it has the smallest atomic radius and highest electronegativity among the alkali metals. This makes lithium the most electropositive and reactive of the group, as it readily loses its single valence electron to form a positive ion (Li+). The periodic trends in atomic radius and electronegativity can be used to predict and explain lithium's tendency to form ionic compounds, its high reactivity with water and other substances, and its ability to participate in a wide range of chemical reactions. Understanding these fundamental periodic properties is crucial for anticipating and interpreting lithium's behavior in various chemical contexts.

Related terms

Alkali Metals: A group of highly reactive metals in the periodic table that includes lithium, sodium, potassium, rubidium, cesium, and francium.

Atomic Radius: The distance from the center of an atom's nucleus to the outermost shell of its electrons, which decreases across a period and increases down a group on the periodic table.

Electronegativity: The ability of an atom to attract shared electrons in a chemical bond, which decreases down a group on the periodic table.