Knowra Sodium Sodium Sodium is a soft, silvery alkali metal with atomic number 11. It reacts readily with water and air and occurs naturally in compounds rather than as a free metal.
Alkali metal : An element in Group 1 of the periodic table, characterized by a single outer electron and high reactivity. Sodium belongs to this family, whose shared outer-electron structure drives similar chemistry.
Sodium hydroxide : A strong, corrosive base with the formula NaOH, also called caustic soda. It is manufactured from sodium chloride and used widely in chemical production.
Atomic number : The number of protons in an atom’s nucleus, which defines its chemical element. Sodium’s atomic number, 11, identifies its nucleus and fixes its place in the periodic table.
Lithium : The lightest alkali metal, with atomic number 3 and chemical properties distinct from heavier group members. Lithium is less reactive with water than sodium, illustrating trends down the alkali-metal group.
Sodium ion : A positively charged sodium atom, usually formed when sodium loses one electron. Losing its outer electron converts metallic sodium into the stable Na⁺ ion found in salts.
Sodium bicarbonate : A compound with the formula NaHCO₃, used in baking, cleaning, and medicine. This familiar sodium compound releases carbon dioxide when heated or combined with acid.
Electron configuration : The arrangement of electrons among an atom’s shells, subshells, and orbitals. Sodium’s configuration ends in 3s¹, explaining why it readily forms Na⁺.
Potassium : An alkali metal with atomic number 19, located directly below sodium in Group 1. Potassium is more reactive than sodium, showing how reactivity generally increases down the group.
Sodium–water reaction : A vigorous reaction in which sodium and water form sodium hydroxide and hydrogen gas. This reaction vividly demonstrates sodium’s tendency to transfer its outer electron.
Sodium-ion battery : A rechargeable battery that stores and releases energy by moving sodium ions between electrodes. It uses sodium’s electrochemistry as a potential alternative to lithium-based storage.
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