Question

Explain the following reactions with example. 1 Reactions of metal with oxygen 2 Reaction of non-metals with water 3. Reaction of metals with dilute acid 4. Reaction of non-metals with base


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Answer 1

Answer:

REACTION WITH BASE - DEFINITION

concept

Metals give hydrogen gas when they react with a base.Reaction of non-metals with bases are complex.

REACTION WITH OXYGEN - DEFINITION

concept

Both metals and non-metals when burnt in oxygen form their oxides. Oxides of metals are basic in nature and oxides of non-metals are acidic in nature.

REACTIONS WITH ACIDS - DEFINITION

concept

Metals give hydrogen gas when they react with dilute acid.Generally, non-metals do not react with dilute acid.

CHEMICAL PROPERTIES - DEFINITION

Metals are very reactive. Metals tend to lose electrons easily and form positively charged ions. Therefore metals are called electropositive elements.Non-metals accept electrons readily because they have high electronegativities.

REACTION OF NON-METAL WITH OXYGEN - DEFINITION

When non-metals react with oxygen the non-metallic oxide is formed. Non-metallic oxides are acidic.

REACTION OF NON-METAL WITH WATER - DEFINITION

Metals react with water to form hydroxides , generally non-metal do not react with water.

Answer 2

Metals and Non-metals

CHAPTER3

I

n Class IX you have learnt about various elements. You have seen

that elements can be classified as metals or non-metals on the basis of

their properties.

n Think of some uses of metals and non-metals in your daily life.

n What properties did you think of while categorising elements

as metals or non-metals?

n How are these properties related to the uses of these elements?

Let us look at some of these properties in detail.

3.1 PHYSICAL PROPERTIES

3.1.1 Metals

The easiest way to start grouping substances is by comparing their

physical properties. Let us study this with the help of the following

activities. For performing Activities 3.1 to 3.6, collect the samples of

following metals – iron, copper, aluminium, magnesium, sodium, lead,

zinc and any other metal that is easily available.

Activity 3.1

n Take samples of iron, copper, aluminium and magnesium. Note

the appearance of each sample.

n Clean the surface of each sample by rubbing them with sand paper

and note their appearance again.

Metals, in their pure state, have a shining surface. This property is

called metallic lustre.

Activity 3.2

n Take small pieces of iron, copper, aluminium, and magnesium.

Try to cut these metals with a sharp knife and note your

observations.

n Hold a piece of sodium metal with a pair of tongs.

CAUTION: Always handle sodium metal with care. Dry i