9781422279472

Hydrogen H 1

the entire universe. In fact, scientists estimate that 90 percent of the atoms in the universe are hydrogen! A typical hydrogen atom contains just one proton and one electron. It is the lightest, simplest atom pos- sible. Under typical conditions, hydrogen is an odorless, colorless gas. According to the Big Bang theory, hydrogen was the first element to form when the universe began. Today, it fuels the fusion process inside every star, including our own sun. Hydrogen also joins with ox- ygen to make H 2 O, or water. Almost all living things on Earth require

The power of hydrogen sent the NASA Space Shuttles into outer space.

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