Molecules ,transport and health.
Chemistry for biologists.
Ionic and covalent bonding.
Biology is the study of living things ,
but living things consist of chemical substances.
The basic unit of all elements is the atom.
When the atoms of two or more different elements react, they form a
compound.
An atom is made up of a nucleus containing positive protons and neutral
neutrons. The nucleus is surrounded by negative electrons.
There are two types of bonding patterns of atoms,
❖ Ionic bonds.
❖ Covalent bonds.
In ionic bonding atoms involved in the reaction receive or give
electrons.
The party that gives electrons are cations while the party that accepts
electrons are anions.
In covalent bonding the electrons are shared between 2 or more atoms.
If their electronegativities are different then electrons get attracted to
one rather than the other.
This uneven distribution of charge within atoms is known as polarity.
Chemical structure of water.
The chemical formula of water is H2O.
It consists of two hydrogen atoms and one oxygen atom.
As their electronegativities are slightly different the electrons get
Attracted more towards the oxygen molecule.
Therefore oxygen atom becomes slightly negative than
Hydrogen atoms.
Therefore water is a polar molecule.
Questions
1. Why is water known as a polar molecule.?
Because the oxygen atom is slightly negative than two hydrogen
atoms as electronegativity of oxygen is high.
2. State separately the charge in each atom of a water molecule.
Oxygen slightly negative.
Hydrogen slightly positive.
Chemistry for biologists.
Ionic and covalent bonding.
Biology is the study of living things ,
but living things consist of chemical substances.
The basic unit of all elements is the atom.
When the atoms of two or more different elements react, they form a
compound.
An atom is made up of a nucleus containing positive protons and neutral
neutrons. The nucleus is surrounded by negative electrons.
There are two types of bonding patterns of atoms,
❖ Ionic bonds.
❖ Covalent bonds.
In ionic bonding atoms involved in the reaction receive or give
electrons.
The party that gives electrons are cations while the party that accepts
electrons are anions.
In covalent bonding the electrons are shared between 2 or more atoms.
If their electronegativities are different then electrons get attracted to
one rather than the other.
This uneven distribution of charge within atoms is known as polarity.
Chemical structure of water.
The chemical formula of water is H2O.
It consists of two hydrogen atoms and one oxygen atom.
As their electronegativities are slightly different the electrons get
Attracted more towards the oxygen molecule.
Therefore oxygen atom becomes slightly negative than
Hydrogen atoms.
Therefore water is a polar molecule.
Questions
1. Why is water known as a polar molecule.?
Because the oxygen atom is slightly negative than two hydrogen
atoms as electronegativity of oxygen is high.
2. State separately the charge in each atom of a water molecule.
Oxygen slightly negative.
Hydrogen slightly positive.
