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Rubidium is a chemical element; it has symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkalin metal group, similar to potassium and caesium. [9] Rubidium is the first alkali metal in the group to have a density higher than water.
This is a list of chemical elements and their atomic properties, ordered by atomic number (Z).. Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus ... 15.37: 1841: 4300 – 1.5: 1.4 ...
The periodic table is a graphic description of the periodic law, [36] which states that the properties and atomic structures of the chemical elements are a periodic function of their atomic number. [37]
Atomic number: 3: 11: 19: 37: 55: 87 Standard atomic weight [note 7] [57] [58] 6.94(1) [note 8] 22.98976928(2) 39.0983(1) 85.4678(3) 132.9054519(2) [223] [note 9 ...
37 is a prime number, [1], a sexy prime, and a Padovan prime 37 is the first irregular prime with irregularity index of 1. [2] 37 is the smallest non-supersingular prime in moonshine theory. 37 is also an emirp because it remains prime when its digits are reversed.
Atomic numbers are sometimes capped at 92 . [20] Definitions based on atomic number have been criticised for including metals with low densities. For example, rubidium in group (column) 1 of the periodic table has an atomic number of 37 but a density of only 1.532 g/cm 3, which is below the threshold figure used by other authors. [21]
The mass number (symbol A, from the German word: Atomgewicht, "atomic weight"), [1] also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It is approximately equal to the atomic (also known as isotopic) mass of the atom expressed in atomic mass units.