Sodium is a chemical element with atomic number 11 and symbol Na (derived from Latin natrium). It is a delicate, silvery-white metal that is extremely reactive. Sodium is an alkali metal because it is in group 1 of the periodic table. 23Na is the only stable isotope. Since the free metal is not found in nature, it must be synthesized from compounds. Sodium, the sixth most common element in the earth's crust, can be found in a variety of minerals such as feldspar, sodalite, and halite (NaCl). Many sodium compounds are highly soluble in water, as the action of water has filtered sodium ions from Earth's minerals through the ages. As a result, sodium and chlorine are the most common dissolved elements by weight in the oceans.
How Sodium Was Discovered?
Humphry Davy's electrolysis of sodium hydroxide resulted in the discovery of sodium in 1807. Sodium hydroxide (lye), a useful sodium compound, is used in soap making, and sodium chloride (edible salt), a de-icing agent and food for animals, including humans, is another important sodium molecule.
Sodium is an essential element for most plants and all animals. Since sodium ions make up the majority of cations in the extracellular fluid (ECF), they also contribute significantly to the volume and osmotic pressure of this fluid. [Hypernatremia is a condition in which sodium concentration is elevated as a result of water loss from the ECF compartment. ECF hypovolemia is a condition in which there is isotonic loss of water and sodium from the ECF compartment, reducing the size of this compartment.
Living human cells use the sodium-potassium pump to exchange three sodium ions for the two potassium ions pumped into the cell. When comparing the ion concentrations inside and outside the cell membrane, potassium is about 40:1 and sodium is about 1:10. When the electrical charge is distributed across the cell membrane of the nerve cells, a nerve impulse – an action potential – can be sent; sodium is very important for this activity.
Sodium is a soft silvery metal at standard temperature and pressure, and unless immersed in oil or an inert gas, which is usually stored as such, it reacts with oxygen in the air to form an off-white sodium oxide. Since sodium metal has only one electron in its valence shell, it has weak metallic bonds and free electrons that can carry energy. This makes sodium metal easier to cut with a knife and makes it a good conductor of electricity and heat. Sodium is one of three metals that can float on water, the other two being lithium and potassium, and is the third least dense of all elemental metals due to its low atomic mass and high atomic radius.
Following periodic patterns throughout the group, the melting (98 °C) and boiling (883 °C) temperatures of sodium are lower than those of lithium but higher than those of the heavier alkali metals potassium, rubidium and cesium. At 1,5 Mbar the color of the substance changes from silvery metallic to black; at 1,9 Mbar the substance becomes transparent with a red tint; At 3 Mbar, sodium is a clear and transparent solid. These properties change rapidly at high pressures. All of these high pressure allotropes are conductors and insulators.
A successful sodium flame test will appear bright yellow.
The excited 3s electrons of sodium produce a photon when they transition from the 3p to the 3s state, and this photon has a wavelength roughly equivalent to the D line at 589,3 nm, causing sodium and its compounds to glow yellow in the flame test. The D line splits at 3 and 589.0 nm by spin-orbit interactions involving the electron in the 589.6p orbital; Hyperfine structures containing both orbitals result in many more lines.
Günceleme: 18/01/2023 14:53