BIOCHEMISTRY – LECTURE ONE
atoms and molecules
The bonding between atoms to form molecules influences the characteristics
that the larger molecule has, which is key to understanding the properties of
larger molecules and how they interact with other molecules.
Atoms consist of a nucleus, which contain protons and neutrons. Outside the
nucleus are electrons. Protons are positive, electrons are negative and neutrons
have no charge.
The atomic number is the number of protons and the atomic mass is the number
of protons and the number of neutrons. There can be variation in the number of
neutrons, which gives an isotope of the same element. It is the number of
protons that defines what element it is.
Level 1 contains a single ‘s’ orbital which can contain a maximum of 2 electrons.
Level 2 contains a ‘s’ orbital and 3 ‘p’ orbitals. Each can hold 2 electrons so
therefore there is a maximum of 8 electrons at level 2. Level 3 is the same.
The outer electron arrangement defines how an atom forms bonds to form larger
molecules. Atoms with similar outer electron arrangements have similar
characteristics.
A molecule is the smallest particle of an element or compound that can exist
independently. A compound is a molecule comprising of more than one type of
element. There are three types of intermolecular bonding – covalent, ionic and
metallic.
o A covalent bond is a bond formed due to electrons from the different
atoms being shared.
o An ionic bond is when an electron is donated / accepted. Oxidation is a
loss of electrons and reduction is gain of electrons.
o Metallic bonding is a fixed nucleus in a sea of electrons.
Valency are numbers used to describe the number of electrons an element
needs to accept / donate to achieve a full outer electron arrangement. The bonds
an atom forms is dictated by its outer electron arrangement.
atoms and molecules
The bonding between atoms to form molecules influences the characteristics
that the larger molecule has, which is key to understanding the properties of
larger molecules and how they interact with other molecules.
Atoms consist of a nucleus, which contain protons and neutrons. Outside the
nucleus are electrons. Protons are positive, electrons are negative and neutrons
have no charge.
The atomic number is the number of protons and the atomic mass is the number
of protons and the number of neutrons. There can be variation in the number of
neutrons, which gives an isotope of the same element. It is the number of
protons that defines what element it is.
Level 1 contains a single ‘s’ orbital which can contain a maximum of 2 electrons.
Level 2 contains a ‘s’ orbital and 3 ‘p’ orbitals. Each can hold 2 electrons so
therefore there is a maximum of 8 electrons at level 2. Level 3 is the same.
The outer electron arrangement defines how an atom forms bonds to form larger
molecules. Atoms with similar outer electron arrangements have similar
characteristics.
A molecule is the smallest particle of an element or compound that can exist
independently. A compound is a molecule comprising of more than one type of
element. There are three types of intermolecular bonding – covalent, ionic and
metallic.
o A covalent bond is a bond formed due to electrons from the different
atoms being shared.
o An ionic bond is when an electron is donated / accepted. Oxidation is a
loss of electrons and reduction is gain of electrons.
o Metallic bonding is a fixed nucleus in a sea of electrons.
Valency are numbers used to describe the number of electrons an element
needs to accept / donate to achieve a full outer electron arrangement. The bonds
an atom forms is dictated by its outer electron arrangement.
