Step 1: Identify the element with Z = 13.
The element with atomic number 13 is Aluminium (Al). It belongs to Group 13 of the periodic table.
Step 2: Write the electronic configuration of Al.
\[ \text{Al}: 1s^2\ 2s^2\ 2p^6\ 3s^2\ 3p^1 \]
Or in abbreviated form: [Ne] \(3s^2\ 3p^1\)
Al has 3 valence electrons in the third shell.
Step 3: Determine the highest oxidation state.
Al has 3 valence electrons (2 in 3s and 1 in 3p). By losing all 3 valence electrons, Al achieves the +3 oxidation state, attaining the noble gas configuration of Ne. This is the highest (and most common) oxidation state.
Step 4: Understand the concept of maximum covalency.
Covalency refers to how many covalent bonds an atom can form. The maximum covalency is determined by the number of orbitals available for bonding. For elements in the third period and beyond, d orbitals can also participate in bonding.
Step 5: Find the maximum covalency of Al.
Al has the configuration [Ne] \(3s^2\ 3p^1\). In the third shell (n=3), there are 3s, 3p, and 3d orbitals available. By hybridising using 3s, 3p, and 3d orbitals, Al can form up to 6 bonds. This is seen in complexes like \([\text{AlF}_6]^{3-}\) where Al is \(sp^3d^2\) hybridised and forms 6 bonds. So the maximum covalency of Al is 6.
Step 6: State the final answer.
For Aluminium (Z = 13): maximum covalency = 6 and highest oxidation state = +3.
\[ \boxed{6,\ +3} \]