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allotrope Some facets exist in several various structural forms, referred to as allotropes. Each allotrope has different physical properties.

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For much more information on the Visual facets image view the Uses and properties section below.

Discovery day 1817
found by Jöns Jacob Berzelius
beginning of the name The surname is acquired from "selene", the Greek name for the Moon.
Allotropes Red Se, Grey Se, black Se


GroupA vertical shaft in the regular table. Members of a group generally have comparable properties and electron configuration in their outer shell.

PeriodA horizontal heat in the routine table. The atomic number of each element increases by one, analysis from left come right.

BlockElements are organised into blocks through the orbital kind in i beg your pardon the outer electrons space found. These blocks are called for the properties spectra lock produce: spicy (s), major (p), diffuse (d), and basic (f).

Atomic numberThe variety of protons in one atom.

Electron configurationThe arrangements of electrons above the critical (closed shell) noble gas.

Melting pointThe temperature in ~ which the solid-fluid phase change occurs.

Boiling point The temperature at which the liquid–gas phase readjust occurs.

SublimationThe shift of a substance directly from the solid to the gas step without passing with a liquid phase.

Density (g cm−3)Density is the mass of a substance that would fill 1 cm3 at room temperature.

Relative atomic massThe fixed of one atom loved one to the of carbon-12. This is roughly the sum of the number of protons and also neutrons in the nucleus. Where much more than one isotope exists, the value provided is the abundance weighted average.

IsotopesAtoms the the same aspect with various numbers that neutrons.

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CAS numberThe chemistry Abstracts organization registry number is a unique identifier of a certain chemical, designed to avoid confusion emerging from various languages and also naming systems.