La belongs to group 3 while Hg belongs to group 12 and both belong to period 6 of the periodic table.

i. La and Hg both belongs to period 6. 

Therefore, 

n = 6.

ii. Elements of group 3 to group 12 belong to the d-block of the modem periodic table.

iii. The general outer electronic configuration of the d-block elements is ns^0-2 (n -1 )^1-10.

iv. Therefore, the outer electronic configuration of all ten elements from La to Hg is as given in the table below.

Element	Outer electronic configuration
La	5d16s2
Hf	5d26s2
Ta	5d36s2
W	5d46s2
Re	5d56s2

Element	Outer electronic configuration
Os	5d66s2
Ir	5d76s2
Pt	5d96s1
Au	5d106s1
Hg	5d106s2

 [Note : There are 14 elements between La and Hf which are called lanthanides. 

Therefore, 

After La, electrons are filled in 4f subshell of lanthanide elements. 

Once all the 14 elements of lanthanide series are filled, next electron enters 5d subshell of Hf. 

Hence,

The outer electronic configurations of Hf to Hg often include completely filled 4f subshell. For example, the electronic configuration of Hf '5d²6s²' can also be written as '4f¹⁴5d²6s²'.]