* Carbon dioxide (CO2): This makes up a whopping 96.5% of the Venusian atmosphere, making it incredibly dense and contributing to the extreme greenhouse effect.

* Nitrogen (N2): This comes in at a distant second, making up about 3.5% of the atmosphere.

There are trace amounts of other gases present, including:

* Sulfur dioxide (SO2): This gas is responsible for the sulfuric acid clouds that blanket Venus.

* Argon (Ar): Found in very small quantities.

* Carbon monoxide (CO): Also found in trace amounts.

* Water vapor (H2O): Exists in extremely small quantities due to the extreme heat.

It's important to note that while Venus has a significant amount of carbon dioxide, it has virtually no oxygen (O2), making it impossible to breathe on the planet.