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The 2s electron is lithium's only valence electron, as the 1s subshell is now too tightly bound to the nucleus to participate in chemical bonding to other atoms: such a shell is called a "core shell". The 1s subshell is a core shell for all elements from lithium onward.
The existence of electron shells was first observed experimentally in Charles Barkla's and Henry Moseley's X-ray absorption studies. Moseley's work did not directly concern the study of electron shells, because he was trying to prove that the periodic table was not arranged by weight, but by the charge of the protons in the nucleus. [9]
Here [Ne] refers to the core electrons which are the same as for the element neon (Ne), the last noble gas before phosphorus in the periodic table. The valence electrons (here 3s 2 3p 3) are written explicitly for all atoms. Electron configurations of elements beyond hassium (element 108) have never been measured; predictions are used below.
The construction of the periodic table ignores these irregularities and is based on ideal electron configurations. [2] Note the non-linear shell ordering, which comes about due to the different energies of smaller and larger shells.
In ionic compounds, lithium loses an electron to become positively charged, forming the cation Li +. Lithium is the first alkali metal in the periodic table, [note 1] and the first metal of any kind in the periodic table. [note 2] At standard temperature and pressure, lithium is a soft, silver-white, highly reactive metal.
Due to having the lowest atomic weight and the largest atomic radius of all the elements in their periods, the alkali metals are the least dense metals in the periodic table. [71] Lithium, sodium, and potassium are the only three metals in the periodic table that are less dense than water: [5] in fact, lithium is the least dense known solid at ...
A period on the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor. Arranged this way, elements in the same group (column) have similar chemical and physical properties, reflecting the periodic law.
competes with other ions such as sodium (immediately below lithium on the periodic table), which like lithium is also a monovalent alkali metal. Lithium also competes with bivalent magnesium ions, whose ionic radius (86 pm) is approximately that of the lithium ion [69] (90 pm). Mechanisms that transport sodium across cellular membranes also ...