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A helium atom is an atom of the chemical element helium. Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing two protons along with two neutrons, depending on the isotope , held together by the strong force .
{{Infobox element}}; labels & notes: (Image) GENERAL PROPERTIES Name Symbol Pronunciation (data central) Alternative name(s) Allotropes Appearance <element> IN THE PERIODIC TABLE Periodic table Atomic number Standard atomic weight (data central) Element category (also header bg color) (sets header bg color, over 'series='-color) Group Period ...
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
Helium is found in large amounts in minerals of uranium and thorium, including uraninite and its varieties cleveite and pitchblende, [20] [137] carnotite and monazite (a group name; "monazite" usually refers to monazite-(Ce)), [138] [139] because they emit alpha particles (helium nuclei, He 2+) to which electrons immediately combine as soon as ...
Hydrogen is the element with atomic number 1; helium, atomic number 2; lithium, atomic number 3; and so on. Each of these names can be further abbreviated by a one- or two-letter chemical symbol; those for hydrogen, helium, and lithium are respectively H, He, and Li. [6] Neutrons do not affect the atom's chemical identity, but do affect its weight.
The helium atom, the smallest of atoms, has a nucleus (pink) consisting of two protons (red) and two neutrons (purple). The fuzzy cloud is the electron probability cloud, with darker regions of the cloud indicating where the electron most likely is.
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.
The symbols are not followed by a period (full stop) as with abbreviations. In most cases, Latin names of elements as used by Berzelius have the same roots as the modern English name. For example, hydrogen has the symbol "H" from Neo-Latin hydrogenium, which has the same Greek roots as English hydrogen. However, in eleven cases Latin (as used ...