An element X of group 16 and period 2 exists as diatomic molecule. It combines with hydrogen and forms ammonia in the presence of a suitable catalyst.
Write the electronic configuration of X and count the number of valence electrons.
Step-1: Introduction
The elemental arrangement of periodic table are placed in periods and groups. The horizontal rows are periods that has rising atomic numbers and vertical columns are groups. 7 periods and 18 groups are in periodic table.
The elements are classified on the basis of electronic configuration.
Step-2: To find the valence electrons
The number of valence shell = Number of period
Since the element belongs to period 2, the valence shell count is 2,
The number of valence electrons + 10 = Number of group
Its group is 15, so it has 5 valence electrons in the outermost shell.
Step-3: To find the electronic configuration
The element with 5 valence electrons and 2 valence shell is Nitrogen ().
Electronic configuration of Nitrogen = (2, 5) with atomic number 7.
Step-3: Reaction of X with Hydrogen
Nitrogen () combines with Hydrogen gas () in the presence of metal catalyst to give Ammonia (). This process is Haber's process.
Final answer
Therefore, Nitrogen has 5 valence electrons and its electronic configuration is (2,5).