Covalent and Metallic bonding

Between what elements do covalent compounds form

Between non metallic elements of similar electro negativity. They share electrons

What are the forces of attraction in covalent compounds

Electrostatic attraction between positively charged nuclei of the atoms and negatively charged pair of electrons

When does a covalent bond form in terms of orbitals

When an atomic orbital containing a single electron from one atom overlaps with an atomic orbital which also contains a single electron of another atom

What type of covalent bond is this

Sigma bond

What type of covalent bond is this

Pi bond (double or triple bond)

What type of bonds are in all polyatomic ions and diatomic molecules

Covalent bonds

Co-ordinate (Dative) bonds

When one atom provides both electrons

Why does the atom accept two electrons in a co-ordinate bond

It is electron deficient

What are the properties of molecular substances

Low melting and boiling points

No conductivity

Sometimes soluble

Metallic bonding

Giant structure of atoms arranged in a regular pattern with delocalised electrons free to move

Properties of metals

Conduct heat and electricity

Malleable and ductile

What is the melting point of group 1 metals

Low due to less charge on ions

What is the melting point of group 2 metals

High melting point due to more charge

What is the melting point of D-block metals

Highest because more delocalized electrons per cation

How is electric current created in metals

Due to the flow of electrons from the negative terminal to the positive terminal

Why are metals good conductors of heat

Because kinetic energy is spread by increasingly vigorous vibrations of closely packed ions

What determines the strength of a metal

Charge on the ion

Size of the ion

How does charge determine strength of a metal

The greater the charge on the ion the greater the the number of delocalised electrons so stronger electrostatic attraction

How does size of the ion determine strength of the metal

The smaller the ion the closer the electrons are to the positive nucleus making the electrostatic attraction stronger

What is the main factor determining the strength of a metal

Charge