On Earth it is relatively rare—5.2 ppm by volume in the atmosphere. Most terrestrial helium<span> present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of </span>helium<span>-4 nuclei.</span>
Answer: The electron configuration of carbon atom is written as 1s²,2s², 2p².
Explanation:
The electronic configuration of an atom is defined as the arrangement of electrons into the shells or orbit of an atom. The constituents of an atom are proton, neutron and electron. the nucleus of an atom, where most of its mass are concentrated, consists of neutrons and protons fused together. Electrons occupy the shells surrounding the nucleus. The shells are lettered K, L, M, N and so on. Numerically, K shell is numbered 1, L is 2 and so on. These numbers also correspond with the increase in the energy level. All the electrons in K shell for instance belong to the first energy level and they have equal energy.
There is a limit to the number of electrons that can be found in a shell. This can be obtained by a formula 2n² where "n" is the energy level number of the shell.
K: 2n² = 2 × 1² = 2
L: 2n² = 2× 2² = 8
These shells are further subdivided into subshells. There are 4 subshells, s, p, d, and f. Each subshell can hold a different number of electrons.
This electron configuration of carbon can be written as 1s² 2s² 2p² where 1s, 2s, and 2p are the occupied subshells, and the superscript "2" is the number of electrons in each of these subshells.
