s-block

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s-block in the periodic table
1218
Group →
↓ Period
11
H
2
He
23
Li
4
Be
311
Na
12
Mg
419
K
20
Ca
537
Rb
38
Sr
655
Cs
56
Ba
787
Fr
88
Ra

The s-block is a block in the periodic table that consists of the first two groups,[1] namely the alkali metals and the alkaline earth metals. The elements in the s-block generally exhibit well-defined trends in their physical and chemical properties, changing steadily moving down the groups. Their properties can be most readily explained in terms of their electron configuration, with their valence electrons occupying s-orbitals. By this definition, hydrogen and helium are sometimes also considered to be part of the s-block.

Properties[edit]

The modern periodic law states that an element's chemical and physical properties is a periodic function of its atomic number. The long form of the periodic table is based on modern periodic law. The long form is divided into four blocks, s, p, d, and f. In an atom of an s-block element,the last electron enters the s-orbital of the outermost electron shell:[2]

Group 1:
Hydrogen (Z=1), Lithium (Z=3), Sodium (Z=11), Potassium (Z=19), Rubidium (Z=37), Caesium (Z=55), Francium (Z=87).
Group 2:
Beryllium (Z=4), Magnesium (Z=12), Calcium (Z=20), Strontium (Z=38), Barium (Z=56), Radium (Z=88).
Anomalous properties of Lithium:
Among alkali metal cations, lithium has the smallest size and highest polarizing power. This separates lithium from its family members. Its covalence character is higher, which is responsible for its solubility in organic solvent.

References[edit]

See also[edit]