2. (a) Explain what is the valence electron is and why the Lewis symbol for an atom
only accounts for electrons in the valence shell of the atom.
(b) Sketch the Lewis Dot Structure for each of the following compounds and
state the molecular geometry.
(c) What is the octet rule and how it is achieved?
2. (a) A valence electron is a single electron or one of two or more electrons in the outer shell of an atom that is responsible for the chemical properties of the atom.
Energy for atomic orbitals increase with increase in the principal quantum number . Atoms with or more electrons have a repulsive force between them hence increase in the order of energy within the shells in the order . The orbital has electrons with lowest energy and the energy increases with increase in orbitals form .
(c) The octet rule states that atoms tend to form compounds in ways that give them eight valence electrons and thus the electron configuration of a noble gas.
The octet rule is achieved through;