What is the proper chemical notation for the anesthesia known as "laughing gas"?

The proper chemical notation for laughing gas is N2O, which stands for dinitrogen oxide. This compound consists of two nitrogen atoms covalently bonded to one oxygen atom. Laughing gas is commonly used in dentistry and surgery as an anesthetic due to its analgesic and anxiolytic effects. Its chemical properties allow it to provide a sense of euphoria, hence the name "laughing gas."

The other options do not represent laughing gas: NO stands for nitric oxide, which has different properties and applications; CO2 is carbon dioxide, a gas that is typically associated with respiration and not anesthetic effects; and NH3 is ammonia, which is a toxic gas and not used in anesthesia at all. Therefore, N2O is the only correct notation among the given choices for laughing gas.