To draw the Lewis structures for HCN (hydrogen cyanide) and HNO3 (nitric acid), we first need to determine the central atom in each molecule.
For HCN, the central atom is carbon (C). The structure is drawn as follows:
- Carbon (C) is bonded to one hydrogen (H) atom and one nitrogen (N) atom. Since carbon can form four bonds and hydrogen can only form one, carbon serves as the central atom.
The Lewis structure looks like this:
H | H - C ≡ N
In HNO3, the central atom is nitrogen (N). This is because nitrogen can bond with multiple oxygen atoms, functioning as a central atom. The Lewis structure is drawn as:
- Nitrogen is connected to three oxygen atoms, where one of the oxygen atoms is double bonded and the other two are singly bonded.
The Lewis structure appears as:
O
||
H - N - O
|
O
In conclusion, the central atom is typically the least electronegative element that can form the most bonds. For HCN, carbon takes that role, while for HNO3, nitrogen is the central atom due to its ability to bond with multiple oxygens.