Hydrogen
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Hydrogen is a chemical element; it has the symbol H and atomic number 1. It is the lightest and most abundant chemical element in the universe, constituting about 75% of all normal matter. Under stand
Purple glow in hydrogen's plasma state.
Robert Boyle, who discovered the reaction between iron filings and dilute acids
Antoine Lavoisier, who identified the element that came to be known as hydrogen
The Hindenburg over New York City in 1937
Nitrogen
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Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common eleme
Liquid nitrogen (N2 at below −196 °C)
Daniel Rutherford, discoverer of nitrogen
Molecular orbital diagram of dinitrogen molecule, N2. There are five bonding orbitals and two antibonding orbitals (marked with an asterisk; orbitals involving the inner 1s electrons not shown), giving a total bond order of three.
Nitrogen trichloride