Sodium is a metallic element with a representation Na and atomic number 11. It is a soft, silvery-white, extremely reactive metal and is a associate of the alkali metals within "group 1". It has only one stable isotope, 23Na.
Sodium reacts exothermically with water small pea-sized pieces will bound across the surface of the water until they are addicted by it, whereas huge pieces will explode. While sodium reacts with water at room temperature, the sodium piece melts with the heat of the reaction to form a sphere, if the reacting sodium piece is huge enough. The reaction with water produce very sarcastic sodium hydroxide and highly flammable hydrogen gas. When burned in air, sodium forms sodium peroxide Na2O2 the oxide Na2O. If burned in oxygen under pressure, sodium superoxide NaO2 will be produced.