Covalent Molecular Bonding

Question 1

Covalent bonding

Answer 1

Forms between two or more atoms - have high electronegativity (relatively full shells - tightly held elections)
i.e. Non metals

Question 2

Covalent bonds

Answer 2

To have full outer shells- atoms share valence electrons by overlapping their outer shells
Shared pair of electrons make up a single bond
Electrons which held more electrons may form double bonds (two shared pairs) or even triple bonds (three shared pairs) or may bond with several atoms

Question 3

Covalent molecules

Answer 3

Molecules are discrete groups of atoms - covalent bonded in together fixed no. of atoms
Molecular formula may be expanded to show the bonding arrangement, using lines or dot diagrams to represent bonds

Question 4

Properties of covalent molecular compounds

Answer 4

Molecules are held together by strong covalent bonds within themselves (intramolecular)
Molecules bonded weakly together by other kinds of forces (intermolecular)
Properties of molecular forces, not the covalent bonds themselves

Question 5

Covalent molecular substances

Answer 5

Relatively low melting point and boiling points (many are gases at room temp)
This tends to increase as the molecules get bigger
As solids, they are soft and waxy
Non-conductors in all states - electrons are tightly held and the molecules themselves are uncharged

Question 6

Covalent networks

Answer 6

Commonly consist of group 4 elements, such as carbon
Also can occur in compounds such as silicon dioxide
Unlimited number of atoms each joined to several others by strong covalent networks or lattices

Question 7

Allotropes

Answer 7

Same element, different arrangement of covalently bonded atoms