Big Bang Theory
Source:https://www.space.com/25126-big-bang-theory.html
The Big Bang Theory is the leading explanation about how the universe began. At its simplest, it
says the universe as we know it started with a small singularity, then inflated over the next 13.8
billion years to the cosmos that we know today.
Light Elements
Source: http://curious.astro.cornell.edu/about-us/84-the-universe/stars-and-starclusters/nuclear-burning/402-how-are-light-and-heavy-elements-formed-advanced
The lightest elements (hydrogen, helium, deuterium, lithium) were produced in the Big Bang
nucleosynthesis. According to the Big Bang theory, the temperatures in the early universe were so
high that fusion reactions could take place. This resulted in the formation of light elements:
hydrogen, deuterium, helium (two isotopes), lithium and trace amounts of beryllium.
Source for Slideshare on Heavy and Light Elements:
https://www.slideshare.net/JeromeJerome1/formation-of-light-and-heavy-elements
Source for Slideshareon ideas of the ancient greeks on the atom PhySci-LC5:
https://www.slideshare.net/bRoKendaRkaNgel03/1-ancient-greek-ideas-about-atomalino?qid=99f5c5f9-f46d-46f9-83bf-912bcab035ed&v=&b=&from_search=3