*for the atomic symbols

Prima Sans BT (Roman) from Bitstream looks very close, but it's not an exact match (for example: /a is a bit different)

Domestos Sans by Gunter Schwarzmaier is also a pretty close match - although the capital M is slightly different; the i is also a bit different, as well.

Looks like something like Vera Sans/DejaVu Sans/Prima Sans. There may be a way to solve it. Click on "Download Page" bottom right, create a new account, download document as PDF then check the Fonts tab under File > Properties ([Command/Ctrl]+D).