Page 60 - NCERT Science Class 10 English Medium

Q U E S T I O N S

1. Metallic oxides of zinc, magnesium and copper were heated with the
following metals.
?
Metal Zinc Magnesium Copper

Zinc oxide
Magnesium oxide
Copper oxide

In which cases will you find displacement reactions taking place?
2. Which metals do not corrode easily?
3. What are alloys?

What you have learnt

n Elements can be classified as metals and non-metals.
n Metals are lustrous, malleable, ductile and are good conductors of heat and
electricity. They are solids at room temperature, except mercury which is a liquid.
n Metals can form positive ions by losing electrons to non-metals.
n Metals combine with oxygen to form basic oxides. Aluminium oxide and zinc oxide
show the properties of both basic as well as acidic oxides. These oxides are known
as amphoteric oxides.

n Different metals have different reactivities with water and dilute acids.
n A list of common metals arranged in order of their decreasing reactivity is known
as an activity series.
n Metals above hydrogen in the Activity series can displace hydrogen from dilute
acids.
n A more reactive metal displaces a less reactive metal from its salt solution.
n Metals occur in nature as free elements or in the form of their compounds.
n The extraction of metals from their ores and then refining them for use is known
as metallurgy.

n An alloy is a homogeneous mixture of two or more metals, or a metal and a
non-metal.
n The surface of some metals, such as iron, is corroded when they are exposed to
moist air for a long period of time. This phenomenon is known as corrosion.
n Non-metals have properties opposite to that of metals. They are neither malleable
nor ductile. They are bad conductors of heat and electricity, except for graphite,
which conducts electricity.

Metals and Non-metals 55

2024-25