Roughly 380,000 years after the Big Bang, matter cooled enough for atoms to form during the era of recombination, resulting in a transparent, electrically neutral gas
These electrons and neutrons formed between the leptons and nucleons age.
The Age of Nucleo-synthesis transitioned to the age of Ions and Atoms.
One has to keep in mind that the formation of the electrons and protons was formed in a couple of seconds due to the intense heat and pressure of the big bang but the formation of atoms took about 300,000 years
After the Era of Atoms the Age of Stars and Galaxies were formed. This took millions of years to form.
wow that unbelievable.
These protons and neutrons made up the basic gases such as Hydrogen, Helium, Lithium.
We still have many unknown ideas about the BIG BANG Theory but one should know that this is beginning of our solar system.