Editing Hydrogen

[[Category:Chemistry]]
== Explanation ==
Hydrogen is the simplest, lightest and the most abundant element in the universe with one proton. This highly reactive element makes up about 75% of the total mass in the universe. Hydrogen occurs naturally in the form of three of its [[isotope|isotopes]] namely, Protium <sup>1</sup>H, Deuterium <sup>2</sup>H, and Tritium <sup>3</sup>H. The most common and stable isotope is Protium, which naturally and very strongly bonds with itself as H<sub>2</sub>. Besides these isotopes, there are synthetic isotopes from <sup>4</sup>H to <sup>7</sup>H.

=== Properties ===

{| class="wikitable"
|-
! Symbol
| H
|-
! [[Atomic number]]
| 1
|-
! [[Atomic mass]]
| 1.007825 g/mol
|-
! [[Melting point]]
| -259.2 °C
|-
! [[Boiling point]]
| -252.8 °C
|-
! [[Density]]
| 0.0899×10<sup>-3</sup> g/cm<sup>3</sup> at STP
|-
! [[Isotope|Isotopes]]
| 3
|}

== Frequently Asked Questions ==
=== Why does Hydrogen lack a neutron? ===
The most common isotope of Hydrogen, Protium (<sup>1</sup>H) is the one that lacks a [[neutron]]. Other isotopes like Deuterium and Tritium have neutrons in them. The reason why Protium is abundant and stable is that in the very beginning, the universe had free protons, [[electron]]s, and neutrons. Due to the short [[mean lifetime]] of the free neutrons, they decayed before they could form enough Deuterium atom. So Protium atoms formed in abundance, being the simplest stable atomic configuration ever.

=== Why doesn't Hydrogen in Sun fuse together all at once? ===
The fusion of Hydrogen in stars is governed by the probability of the hydrogen atoms colliding with enough energy to [[nuclear fusion|fuse]] into [[Helium]]. Most hydrogen atoms in our [[Sun]] repels due to the electrostatic repulsion between them. But with enough time, some hydrogen atoms tunnel through the electrostatic repulsion and fuse to form Helium-4. This phenomenon is known as [[quantum tunnelling]]. But the chances of that Helium-4 nucleus undergoing a [[beta decay]] and forming deuterium, which further carries on the nuclear fusion reaction, are slim. These conditions in our Sun are the key factor why all the Hydrogen in it never fuse all together at once. In the case of heavier stars, where [[gravity]] and [[temperature]] are very high, the rate of fusion could be much faster.