1. General Information
- Symbol: Li
- Atomic Number: 3
- Atomic Mass: 6.94 u
- Category: Alkali Metal
- Group: 1 (Alkali Metals)
- Period: 2
- Electron Configuration: 1s² 2s¹
- Density: 0.534 g/cm³ (lightest solid element)
- Color: Silvery-white
- Melting Point: 180.54°C (353°F)
- Boiling Point: 1590°C (2894°F)
- Electronegativity: 0.98 (Pauling scale)
Electron Configuration:
Lithium’s electron configuration is 1s² 2s¹. It has two electrons in its first shell and one electron in its second shell.
2. Position in the Periodic Table
Lithium is the first alkali metal, located in Group 1, Period 2 of the periodic table.
- Alkali metals: All alkali metals (Group 1 elements) are highly reactive, with one electron in their outermost shell.
3. Physical Properties
- Appearance: Lithium is a soft, silvery-white metal that is the lightest of all metals.
- Density: Lithium is less dense than water, which is why it can float.
- Conductivity: It is a good conductor of electricity and heat.
- Hardness: It is relatively soft compared to other metals and can be cut with a knife.
4. Chemical Properties
- Reactivity: Lithium is highly reactive and must be stored in oil to prevent it from reacting with moisture in the air. It reacts vigorously with water to produce hydrogen gas and lithium hydroxide. Reaction with water: 2Li(s)+2H2O(l)→2LiOH(aq)+H2(g)2Li(s) + 2H_2O(l) → 2LiOH(aq) + H_2(g)2Li(s)+2H2O(l)→2LiOH(aq)+H2(g)
- Flame Test: Lithium produces a characteristic crimson or red flame when heated in a flame.
5. Uses of Lithium
- Batteries: Lithium is widely used in rechargeable lithium-ion batteries, which power devices like smartphones, laptops, and electric vehicles.
- Alloys: Lithium is used to make strong, lightweight alloys, particularly for aerospace applications.
- Medication: Lithium salts (like lithium carbonate) are used in the treatment of bipolar disorder, as it helps stabilize mood swings.
- Heat-resistant Glass and Ceramics: Lithium is used in the production of heat-resistant glass, ceramics, and in controlling the melting points of these materials.
6. Isotopes of Lithium
Lithium has two stable isotopes:
- Lithium-6 (Li-6): An isotope of lithium that makes up about 7.5% of natural lithium.
- Lithium-7 (Li-7): The most abundant isotope of lithium, making up about 92.5% of natural lithium.
Isotope Data:
| Isotope | Abundance (%) | Atomic Mass (u) |
|---|---|---|
| Li-6 | 7.5 | 6.015 |
| Li-7 | 92.5 | 7.016 |
7. Trends in the Periodic Table
- Alkali Metals: As we move down Group 1, the reactivity increases, the melting point decreases, and the atomic radius increases.
- Lithium vs Sodium (Na) vs Potassium (K):
- Reactivity: Lithium is less reactive compared to sodium and potassium.
- Melting Points: Lithium has the highest melting point among the alkali metals.
- Atomic Radius: Lithium has the smallest atomic radius in Group 1.
- Lithium vs Sodium (Na) vs Potassium (K):
Graph – Alkali Metals Reactivity Trend:
plaintextCopyReactivity (Increasing Downwards):
Li < Na < K < Rb < Cs
8. Safety and Handling
- Storage: Lithium should be stored under oil to prevent contact with moisture or air.
- Toxicity: While lithium is essential in the human body in trace amounts, high concentrations can be toxic. Always handle lithium carefully, especially in battery form.
- Fire Risk: Lithium reacts violently with water, and its flame can be dangerous. Special extinguishers, such as class D fire extinguishers, are required for lithium fires.
9. Table of Important Properties:
| Property | Value |
|---|---|
| Atomic Number | 3 |
| Atomic Mass | 6.94 u |
| Electron Configuration | 1s² 2s¹ |
| Density | 0.534 g/cm³ |
| Melting Point | 180.54°C |
| Boiling Point | 1590°C |
| Reactivity with Water | High |
| Flame Color | Crimson/Red |
10. Lithium in Nature
- Occurrence: Lithium is the 25th most abundant element in the Earth’s crust. It is primarily found in minerals like spodumene, lepidolite, and petalite. It is also present in salt lakes, such as those found in parts of South America.
11. Conclusion
Lithium is a crucial element in various modern applications, especially in energy storage and electronics. Its high reactivity and light weight make it unique among the alkali metals, and its importance in battery technology makes it indispensable for sustainable energy solutions.
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