What is the second most abundant gas in Venus's atmosphere?

What is the second most abundant gas in Venus's atmosphere? Nitrogen is the answer.

Venus's atmosphere is overwhelmingly carbon dioxide, which makes up about 96.5% by volume. Nitrogen accounts for roughly 3.5%, making it the second most abundant gas. The remaining gases occur only in trace quantities, with sulfur dioxide especially notable because it helps form Venus's dense sulfuric-acid clouds.

Venus's nitrogen percentage is tiny compared with Earth's atmosphere, where nitrogen makes up about 78%. Yet Venus has such a massive atmosphere that its total nitrogen content is estimated to be roughly four times greater than Earth's. The planet's surface pressure is about 93 times Earth's sea-level pressure.

A common mix-up is choosing oxygen because oxygen is Earth's second-most abundant atmospheric gas. Venus, however, has only trace oxygen and virtually no free oxygen suitable for breathing. The planet's carbon-dioxide-rich air also drives an extreme greenhouse effect, producing surface temperatures near 467°C.