What type of ligand is ethylenediamine?

Identify the neutral ligand from the following.

The number of ligands which are directly bonded to the metal is known as

Which of the following is a negative ligand?

Consider the following statements according to Werner's theory:
$(a)$ Ligands are connected to the metal ions by coordinate bonds.
$(b)$ Secondary valencies have directional properties.
$(c)$ Secondary valencies are non-ionisable.
Of these statements:

State the rules for writing the formula of a mononuclear coordination species.