Metals and Non-Metals

Chemical properties of Non-Metals -

1. Reaction with oxygen :-

Acidic oxides or neutral oxides of non-metals are formed which dissolve in water to form acids.

S + O2 → SO2

SO2 + H2O → H2SO3 (Sulphurous acid)

2. Reaction with water :-

Hydrogen gas is evolved .

3. Reaction with Dilute Acids :-

No reaction takes place.

4. Reaction with Salt Solutions :-

A more reactive non-metal displaces a less reactive non-metal from its salt solution.

5. Reaction with Chlorine :-

They react with chlorine to form covalent chlorides which are non-electrolytes (do not conduct electricity).

6. Reaction with Hydrogen :-

They form covalent hydrides because non-metal atoms cannot give electrons to hydrogen atoms to form hydride ions.

USES of Non-Metals :-

    1. Hydrogen is used in making vanaspati ghee , ammonia.
    2. Carbon is used for making dry cells.
    3. Nitrogen is used in fertilizers , as preservatives of food items.

Reaction of Metals and Non-Metals :-

When metals react with Non-Metals , they form ionic compounds.

When non-metals react with other non-metals, they form covalent bonds.

Noble / Inert Gases :- Gases which do not react with other elements to form compounds . i.e. helium, neon, argon, Krypton, Xenon and Radon.

IONS :-

An ion is an electrically charged atom,

Na+ , Mg2+ , Cl- , O2-

Two types of ions - Anion ; Cation

1. Anion :-

Negatively charged ion; formed by the gain of one or more electrons by an atom. It contains more electrons than protons.

Cl + e- → Cl-

 If an element has 5,6 or 7 electrons in the outermost shell of its atom, then it gains electrons to achieve the stable electron configuration of 8 valence electrons.

2. Cation :-

If an element has 1, 2 or 3 electrons in the outermost shell of its atoms, then it loses these electrons to achieve the inert gas electron arrangement of eight valence electrons and forms positively charged ion or cation.

Na - e- → Na+

 

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