Carbon and Its Compounds
Soaps and Detergents:-
Cleansing Action of Soap
When soap is added to water, the soap molecules uniquely orient themselves to form
spherical shape micelles.
The non-polar hydrophobic part or tail of the soap molecules attracts the dirt or oil part of
the fabric, while the polar hydrophilic part or head,(−COO N a , remains attracted to water
− +
molecules.
The agitation or scrubbing of the fabric helps the micelles to carry the oil or dirt particles
and detach them from the fibres of the fabric.
,Hard Water
Hard water contains salts of calcium and magnesium, principally as bicarbonates, chlorides,
and sulphates. When soap is added to hard water, calcium and magnesium ions of hard
water react with soap forming insoluble curdy white precipitates of calcium and magnesium
salts of fatty acids.
2C17 H35 COON a + M gCl2 → (C17 H35 COO)2 M g + 2N aCl
2C17 H35 COON a + CaCl2 → (C17 H35 COO)2 Ca + 2N aCl
These precipitates stick to the fabric being washed and hence, interfere with the cleaning
ability of the soap. Therefore, a lot of soap is wasted if water is hard.
Covalent Bonds
Difficulty of Carbon to Form a Stable Ion
To achieve the electronic configuration of nearest noble gas, He, if the carbon atom loses
four of its valence electrons, a huge amount of energy is involved. C ion hence formed will
4+
be highly unstable due to the presence of six protons and two electrons.
If the carbon atom gains four electrons to achieve the nearest electronic configuration of
the noble gas, Ne, C ion will be formed. But again, a huge amount of energy is required.
4−
Moreover, in C ion it is difficult for 6 protons to hold 10 electrons. Hence, to satisfy its
4+
tetravalency, carbon shares all four of its valence electrons and forms covalent bonds.
Ionic Bond
, Ionic bonding involves the transfer of valence electron/s, primarily between a metal and a
nonmetal. The electrostatic attractions between the oppositely charged ions hold the
compound together.
Ionic compounds:
1. Are usually crystalline solids (made of ions)
2. Have high melting and boiling points
3. Conduct electricity when melted
4. Are mostly soluble in water and polar solvents
Covalent Bond
A covalent bond is formed when pairs of electrons are shared between two atoms. It is
primarily formed between two same nonmetallic atoms or between nonmetallic atoms with
similar electronegativity.
Lewis Dot Structure
Lewis structures are also known as Lewis dot structures or electron dot structures.
These are basically diagrams with the element's symbol in the centre. The dots around it
represent the valence electrons of the element.
Lewis structures of elements with atomic number 5-8
Covalent Bonding in H2, N2 and O2
Formation of a single bond in a hydrogen molecule:
Each hydrogen atom has a single electron in the valence shell. It requires one more to
acquire nearest noble gas configuration (He).
Therefore, both the atoms share one electron each and form a single bond.
Soaps and Detergents:-
Cleansing Action of Soap
When soap is added to water, the soap molecules uniquely orient themselves to form
spherical shape micelles.
The non-polar hydrophobic part or tail of the soap molecules attracts the dirt or oil part of
the fabric, while the polar hydrophilic part or head,(−COO N a , remains attracted to water
− +
molecules.
The agitation or scrubbing of the fabric helps the micelles to carry the oil or dirt particles
and detach them from the fibres of the fabric.
,Hard Water
Hard water contains salts of calcium and magnesium, principally as bicarbonates, chlorides,
and sulphates. When soap is added to hard water, calcium and magnesium ions of hard
water react with soap forming insoluble curdy white precipitates of calcium and magnesium
salts of fatty acids.
2C17 H35 COON a + M gCl2 → (C17 H35 COO)2 M g + 2N aCl
2C17 H35 COON a + CaCl2 → (C17 H35 COO)2 Ca + 2N aCl
These precipitates stick to the fabric being washed and hence, interfere with the cleaning
ability of the soap. Therefore, a lot of soap is wasted if water is hard.
Covalent Bonds
Difficulty of Carbon to Form a Stable Ion
To achieve the electronic configuration of nearest noble gas, He, if the carbon atom loses
four of its valence electrons, a huge amount of energy is involved. C ion hence formed will
4+
be highly unstable due to the presence of six protons and two electrons.
If the carbon atom gains four electrons to achieve the nearest electronic configuration of
the noble gas, Ne, C ion will be formed. But again, a huge amount of energy is required.
4−
Moreover, in C ion it is difficult for 6 protons to hold 10 electrons. Hence, to satisfy its
4+
tetravalency, carbon shares all four of its valence electrons and forms covalent bonds.
Ionic Bond
, Ionic bonding involves the transfer of valence electron/s, primarily between a metal and a
nonmetal. The electrostatic attractions between the oppositely charged ions hold the
compound together.
Ionic compounds:
1. Are usually crystalline solids (made of ions)
2. Have high melting and boiling points
3. Conduct electricity when melted
4. Are mostly soluble in water and polar solvents
Covalent Bond
A covalent bond is formed when pairs of electrons are shared between two atoms. It is
primarily formed between two same nonmetallic atoms or between nonmetallic atoms with
similar electronegativity.
Lewis Dot Structure
Lewis structures are also known as Lewis dot structures or electron dot structures.
These are basically diagrams with the element's symbol in the centre. The dots around it
represent the valence electrons of the element.
Lewis structures of elements with atomic number 5-8
Covalent Bonding in H2, N2 and O2
Formation of a single bond in a hydrogen molecule:
Each hydrogen atom has a single electron in the valence shell. It requires one more to
acquire nearest noble gas configuration (He).
Therefore, both the atoms share one electron each and form a single bond.
