# Combining chemical elements

Prof Brian Cox mentioned on Wonders of the Universe when discussing chemical elements that Carbon 12 consists of 6 protons and 6 neutrons, he also mentioned that Helium consists of 2 protons and 2 neutrons. He then went on to say that by combining certain elements we can create others - can anyone explain what he means by this with a practical example?

Can I get myself some Carbon and some Helium and somehow combine them? :)

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$$^4_2He + ^{12}_6C \rightarrow ^{16}_8O +\gamma$$ This is an alpha process, and does happen inside certain stars.