Atomic Properties of Na
- Atomic Number of Na
- 11
- Atomic Mass of Na
- 22.9900 u
- Electron Configuration
- [Ne] 3s1
- Electronegativity
- 0.93
- Block
- s-block
- Group
- 1
- Period
- 3
Cut sodium metal and a fresh silvery surface appears, then quickly dulls as it reacts with air. Place it in water and the reaction produces sodium hydroxide, hydrogen gas, and heat. The metal may melt into a moving bead, and the hydrogen can ignite. Sodium therefore travels through laboratories under oil, far removed from the form encountered at a dinner table.
In sodium chloride, sodium has already lost an electron and exists as Na+. Chloride carries the opposite charge, and the ions assemble into a stable crystal lattice. Dissolve the salt and those ions separate into water, where sodium becomes essential to fluid balance and electrical signaling. Nerve impulses depend on controlled sodium movement across cell membranes, coordinated with potassium and powered by ion pumps. The body needs sodium, though excessive dietary intake can contribute to high blood pressure in susceptible people.
Excited sodium atoms provide another signature. They emit intense yellow light near 589 nanometers, producing the familiar glow of low-pressure sodium lamps and a strong yellow flame-test color. Spectroscopy turns that color into identification.
Industry isolates sodium by electrolyzing molten sodium chloride because water would react before sodium metal could collect. Pure sodium has specialized roles, including heat transfer in some reactor designs, while its many compounds support glass, chemicals, medicine, and agriculture.
Sodium starts sparks because its outer electron is easily removed. The useful lesson arrives after that spark: elemental sodium, Na+ in a nerve, and sodium chloride in food are chemically distinct forms whose behavior cannot be inferred from the name alone.