Pogson and Lieutenant John Herschel, and was subsequently confirmed by French astronomer, Jules Janssen. Janssen is often jointly credited with detecting the element, along with Norman Lockyer. It was first detected as an unknown, yellow spectral line signature in sunlight, during a solar eclipse in 1868 by Georges Rayet, Captain C. Helium is named for the Greek Titan of the Sun, Helios. Large amounts of new helium are being created by nuclear fusion of hydrogen in stars. Most helium in the universe is helium-4, the vast majority of which was formed during the Big Bang. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay.

This is due to the very high nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. Its abundance is similar to this in both the Sun and in Jupiter. It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Helium is the second lightest and second most abundant element in the observable universe (hydrogen is the lightest and most abundant). Its boiling point is the lowest among all the elements. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first noble gas in the periodic table. Such an arrangement helps explain the periodicity and periodic trends observed across the elements of the periodic table.Helium is a chemical element with the symbol He and atomic number 2. The N shell containing 4s, 4d, 4p and 4f, can carry 32 electrons. The M shell contains 3s, 3p, and 3d, and can carry 18 electrons. The K shell contains a 1s subshell hence it can carry 2 electrons, the L shell has 2s and 2p, and can carry 8 electrons. This decides the electron capacity of the shells. The maximum electrons that can be carried by the sub-shell S is 2, by P is 6, by D is 10, and the F sub-shell can carry 14. Each shell and subshell have a limitation on the amount of electrons that it can carry. The subshells have a distinct shape and configuration, in which the electrons move freely. They stand for sharp (S), principal (P), diffuse (D), and fundamental (F). The shells are labeled K, L, M, N, and so on, from the innermost to the outermost shell.Įach shell has subshells that are named for the type of emission lines produced from different states of angular momentum. This model has been widely accepted, and according to it, each atom has shells, which further have subshells. It involves the specific arrangement of electrons in shells and sub-shells of Bohr’s atomic model. The concept of electronic configuration has replaced the older concept of valency and valence electrons. The electronic configuration of each element is decided by the Aufbau principle which states that the electrons fill orbitals in order of increasing energy levels. This article provides you with an electronic configuration chart for all these elements. Each element has a unique atomic structure that is influenced by its electronic configuration, which is the distribution of electrons across different orbitals of an atom.

There are 118 elements in the periodic table.

Helium electron configuration