Hydrogen is the lightest element.
Uses and research
It occurs in water and many fuels, and nuclear fusion of hydrogen powers stars.
Nonmetals take many forms
Nonmetals do not all share one appearance or behavior. Some are gases, others solids, and different structures of the same element can have different properties, as graphite and diamond demonstrate. After identifying the atom type, ask how atoms are combined: as individual atoms, molecules or extended structures.
What the atomic number tells us
Hydrogen has atomic number 1. This is the number of protons in its nucleus. A neutral atom also has 1 electrons. Losing or gaining electrons makes an ion; it does not change the element unless the proton count changes.
The model's rings help count electrons by shell. They are not actual circular paths. A model of one atom and the properties of a whole material are different levels of description.
Temperature and state
25°C: Gas
Illustrative particle motion: sizes, distances and speeds are not to scale. Particles represent atoms or molecules.
← CoolHeat →
Melting point -259.34°C / Boiling point -252.87°C
Pure element at 1 atmosphere. Image conditions are explained in captions. Pictures do not change with temperature.