Question 1: Define alkali metals and state their general position in the periodic table.

Answer: Alkali metals are the elements in Group 1 of the periodic table, including lithium, sodium, potassium, rubidium, caesium, and francium. They are highly reactive metals with one outer electron.

Question 2: Explain why alkali metals are stored under oil.

Answer: Because they react rapidly with moisture and oxygen in the air, alkali metals are stored under oil to prevent oxidation and reaction with water.

Question 3: Describe the trend in reactivity of alkali metals as you move down Group 1.

Answer: Reactivity increases as you move down Group 1 because the outer electron is more easily lost due to increased atomic size and electron shielding.

Question 4: What is the main reason for the high reactivity of alkali metals?

Answer: Because they have a single outer electron that they readily lose to form positive ions, making them highly reactive.

Question 1: Describe what happens when sodium reacts with water.

Answer: Sodium reacts vigorously with water, producing sodium hydroxide and hydrogen gas. The reaction is exothermic and can cause the hydrogen to ignite. The reaction can be represented as: 2Na + 2H2O → 2NaOH + H2.

Question 2: Write the chemical formula for the compound formed when potassium reacts with chlorine.

Answer: KCl (potassium chloride)

Question 3: Which alkali metal produces the most violent reaction with water? A) Lithium B) Sodium C) Potassium D) Caesium

Answer: Caesium

Question 1: Describe a typical safety precaution when handling alkali metals in a laboratory setting.

Answer: Alkali metals should be handled using tongs and stored under oil or in an inert atmosphere to prevent accidental reactions with moisture or oxygen.

Question 2: Explain one industrial application of lithium and its importance.

Answer: Lithium is used in rechargeable batteries for electronic devices such as smartphones and laptops. Its high electrochemical potential and light weight make it ideal for portable power sources.

Question 3: Provide an example of how alkali metals are used in medicine.

Answer: Lithium compounds are used to treat bipolar disorder by stabilising mood swings.

Question 1: A sample of an alkali metal reacts with water, producing a gas that ignites with a squeal. Which metal is most likely involved? State your reasoning.

Answer: The metal is most likely potassium or caesium, with caesium being the most reactive. The ignition with a squeal indicates a vigorous hydrogen release, typical of heavier alkali metals further down Group 1.

Question 2: A student observes that lithium reacts less vigorously with water than sodium. Explain why this is consistent with the reactivity trend in Group 1.

Answer: Because lithium is higher up in Group 1, its outer electron is more tightly held, making it less reactive than sodium, which is further down and loses its outer electron more easily.

Question 1: Summarise the key properties of alkali metals that make them unique among metals.

Answer: Alkali metals are soft, low-density, highly reactive metals with a single electron in their outer shell. They react vigorously with water and oxygen, forming alkaline solutions and hydrogen gas. Their reactivity increases down the group, and they are used in various applications such as batteries, medicine, and industry due to their unique chemical properties.