Hydrogen and helium were the first elements to be made because they are the simplest. Hydrogen has one proton in its nucleus, so we say it has atomic number 1. Helium has two protons in its nucleus, so its atomic number is 2. When the CMBR was emitted, about 380,000 years after the big bang, there was also a sprinkling of lithium (atomic number 3) and beryllium (atomic number 4). And that was it. These were the only elements created in the big bang. The Goldilocks conditions for creating more elements with larger nuclei were simple: lots of protons and very high temperatures, temperatures that
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