Which Statement About The Alkali Metals Is Correct?
The correct statement about the alkali metals is that they are highly reactive elements. Alkali metals are found in Group 1 of the periodic table. They include lithium, sodium, potassium, rubidium, cesium, and francium. These metals are soft, shiny, and have low melting points. Alkali metals easily lose their outermost electron to form positive ions. This characteristic makes them highly reactive with other elements. Their reactivity increases as you move down the group. Due to their high reactivity, alkali metals are never found in their pure form in nature. Instead, they are usually stored in oil to prevent them from reacting with moisture in the air.
Contents
| Alkali metals are highly reactive and have one electron in their outer shell. |
| Alkali metals are soft and can be easily cut with a knife. |
| Alkali metals have low melting and boiling points. |
| Alkali metals are usually stored under oil to prevent reaction with air. |
| Alkali metals react vigorously with water to produce hydrogen gas. |
- Lithium is the lightest alkali metal with atomic number 3.
- Alkali metals are located in Group 1 of the periodic table.
- Alkali metals have a silvery appearance and are good conductors of electricity.
- Alkali metals are used in fireworks to produce vibrant colors.
- Alkali metals form ionic compounds with non-metals.
What Are the Properties of Alkali Metals?
Alkali metals are the elements found in Group 1 of the periodic table. They are highly reactive and have one electron in their outermost shell. These metals are soft, shiny, and have low melting points. They are excellent conductors of electricity and are typically stored in oil to prevent reactions with moisture in the air.
- Highly reactive
- Soft and shiny
- Low melting points
- Excellent conductors of electricity
Why Are Alkali Metals Stored in Oil?
Alkali metals are stored in oil to prevent reactions with moisture in the air. When exposed to air, alkali metals can react violently, forming oxides and hydroxides. By storing them in oil, the metals are protected from exposure to air and moisture, ensuring their stability until they are ready for use.
| Prevents reactions with moisture | Protects metals from air exposure |
How Do Alkali Metals React with Water?
Alkali metals react vigorously with water, producing hydrogen gas and a metal hydroxide. This reaction is highly exothermic, meaning it releases a significant amount of heat. The reactivity of alkali metals with water increases as you move down the group from lithium to cesium, with cesium being the most reactive.
- Produces hydrogen gas
- Forms metal hydroxide
- Exothermic reaction
- Reactivity increases down the group
Which Alkali Metal Is the Most Reactive?
Among the alkali metals, cesium is the most reactive. Cesium reacts violently with water, producing hydrogen gas and heat. Due to its extreme reactivity, cesium is handled with extreme caution in laboratory settings to prevent accidents.
| Cesium is the most reactive | Reacts violently with water |
What Color Flame Do Alkali Metals Produce?
Alkali metals produce a characteristic colorful flame when they are burned. Each alkali metal emits a specific color when burned, with lithium producing a crimson flame, sodium a bright yellow flame, and potassium a lilac flame. This flame test is a common way to identify alkali metals.
- Lithium – crimson flame
- Sodium – bright yellow flame
- Potassium – lilac flame
How Are Alkali Metals Used in Everyday Life?
Alkali metals have various applications in everyday life. Sodium, for example, is used in table salt (sodium chloride) and in soap production. Potassium is essential for plant growth and is commonly found in fertilizers. Lithium is used in rechargeable batteries, while cesium has applications in atomic clocks.
| Sodium in table salt and soap | Potassium in fertilizers |
| Lithium in rechargeable batteries | Cesium in atomic clocks |
Which Alkali Metal Is Used in Nuclear Reactors?
Cesium is used in nuclear reactors as a coolant due to its high atomic mass and ability to absorb neutrons. Cesium-137, a radioactive isotope of cesium, is produced in nuclear reactions and has applications in radiation therapy and industrial gauges.
- Cesium used as a coolant in nuclear reactors
- Cesium-137 in radiation therapy
Are Alkali Metals Good Conductors of Electricity?</h
Alkali metals are excellent conductors of electricity due to the presence of a single electron in their outermost shell. This electron can move freely, allowing for the flow of electric current. The conductivity of alkali metals makes them valuable in various electronic applications.
| Excellent conductors of electricity | Single electron in outer shell allows for conductivity |
What Is the Density of Alkali Metals?
Alkali metals have low densities compared to other metals. The density of alkali metals decreases as you move down the group from lithium to cesium. For example, lithium has a density of approximately 0.53 g/cm³, while cesium has a density of around 1.93 g/cm³.
- Density decreases down the group
- Lithium – 0.53 g/cm³
- Cesium – 1.93 g/cm³