A covalent bond is a shared pair of electrons. Covalent bonding results in the formation of molecules. Simple molecular substances have low melting and boiling points, and do not conduct electricity.
How is a covalent bond formed?
By sharing pairs of electrons between two atoms
By transferring electrons to form oppositely charged ions
By delocalising outer electrons in a lattice of positive ions
What combination of elements will form covalent bonds?
Metal atom and another metal atom
Metals atom and non-metal atom
Non-metal atom and another non-metal atom
What does this diagram of hydrogen chloride show about the bond being formed?
The atoms share all eight electrons, one from the hydrogen atom and seven from the chlorine atom
The bond is formed by sharing a pair of electrons, one from the hydrogen atom and one from the chlorine atom
An electron is transferred from the hydrogen atom onto the chlorine atom to form ions
How many covalent bonds will phosphorous (in group 5) usually form?
Which of the following have molecules which are held together by three covalent bonds?
Water - H2O
Carbon dioxide - CO2
Ammonia - NH3
How many atoms are in a molecule of methane?
How many shared pairs of electrons are there in a water molecule, formula H2O?
Which statement about simple covalent molecules is correct?
Strong bonds between atoms in molecules, but weak forces between molecules
Weak bonds between atoms in molecules, and weak forces between molecules
Weak bonds between atoms in molecules, but strong forces between molecules
Which is a typical property of covalent substances made from small molecules?
High melting points
Do not conduct electricity
Mostly hard solids
What force is overcome when covalent molecular substances melt or boil?
Covalent bonds in molecules
Electrostatic forces between ions