According a Wikipedia article, right after the Big Bang there was about 74% hydrogen-1, 1% hydrogen-2, 25% helium-4, and trace amounts of lithium and beryllium. Nucleosynthesis stopped there because there are no stable 8-nucleon elements (2 x helium-4) and there was insufficient time for many triple-alpha collisions (3 x helium-4).
http://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis