9. Metals (Part 2) (2/3) (Cambridge IGCSE Chemistry 0620 for 2023, 2024 & 2025)

Summary

This video delves into the reactivity series of metals, explaining how different metals react with water, acids, and oxygen. It provides an in-depth look at the order of reactivity, from potassium to gold, and illustrates key concepts like displacement reactions and the behavior of metals with various substances. The video emphasizes the ease with which metals lose electrons, their reactivity with cold water and dilute acids, and the role of protective oxide layers, such as in aluminium. This revision session helps students understand and memorize the reactivity series for IGCSE chemistry.

Takeaways

• 😀 The reactivity series ranks metals from most reactive to least reactive, including potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, hydrogen, copper, silver, and gold.
• 😀 A useful mnemonic to remember the reactivity series is: 'Please stop calling me a cute zebra. I have collected shiny gold.'
• 😀 The reactivity of a metal refers to how easily it loses electrons to form positive ions, with more reactive metals losing electrons more easily.
• 😀 Displacement reactions occur when a more reactive metal displaces a less reactive one from a compound.
• 😀 For example, magnesium can displace zinc, iron, copper, and silver from their salt solutions, while silver cannot displace any of these metals.
• 😀 Highly reactive metals like potassium, sodium, and calcium react vigorously with cold water to produce hydrogen gas and metal hydroxides.
• 😀 Magnesium does not react with cold water but reacts with steam to form magnesium oxide and hydrogen gas.
• 😀 Metals like magnesium and zinc react quickly with dilute hydrochloric acid to produce salts and hydrogen gas, while less reactive metals like copper do not react.
• 😀 The reactivity of metals with acids decreases as you move down the reactivity series, with magnesium reacting the most vigorously and gold the least.
• 😀 Aluminium seems unreactive because it forms a thin oxide layer when exposed to air, preventing further reactions with water or acids.

Q & A

What is the reactivity series of metals?

The reactivity series is a list that ranks metals from most reactive to least reactive. The order is: Potassium, Sodium, Calcium, Magnesium, Aluminium, Carbon, Zinc, Iron, Hydrogen, Copper, Silver, and Gold.

Why are hydrogen and carbon included in the reactivity series?

Although hydrogen and carbon are not metals, they are included in the reactivity series because they are involved in the extraction of metals from their oxides.

How does the reactivity of metals relate to their ability to lose electrons?

A metal's reactivity refers to how easily it loses electrons to form positive ions. More reactive metals lose electrons more easily, while less reactive metals lose electrons less readily.

What is a displacement reaction and how does it relate to the reactivity series?

A displacement reaction occurs when a more reactive element replaces a less reactive element in a compound. In metals, a more reactive metal can displace a less reactive metal from its compound, which is how the reactivity series is determined.

Give an example of a displacement reaction involving metals.

For example, magnesium reacts with zinc, iron, copper, and silver salt solutions to displace them, showing that magnesium is more reactive than these metals.

How do highly reactive metals like potassium, sodium, and calcium react with cold water?

Highly reactive metals such as potassium, sodium, and calcium react vigorously with cold water to produce metal hydroxides and hydrogen gas. Potassium's reaction is the most intense, often igniting the hydrogen gas.

What happens when magnesium reacts with cold water and steam?

Magnesium does not react with cold water but reacts with steam to form magnesium oxide and hydrogen gas. This reaction is less vigorous compared to the reactions of potassium, sodium, or calcium with cold water.

Why do copper, silver, and gold not react with dilute hydrochloric acid?

Copper, silver, and gold are less reactive than hydrogen, which is why they do not react with dilute hydrochloric acid.

What makes aluminium appear unreactive even though it is a reactive metal?

Aluminium forms a thin protective layer of aluminium oxide when exposed to air, which prevents further reactions with water, acids, or other substances, making it appear unreactive.

How can the reactivity of metals be ranked experimentally?

The reactivity of metals can be ranked by observing their reactions with water, acids, and oxygen. The speed and intensity of these reactions help determine the order of reactivity, from most to least reactive.