Atom
Free PNG images in the category “Atom”: 1 files with transparent background, no sign-up.
Chemistry drawn at the scale of molecules: skeletal formulas of ring compounds, atoms labelled in their bonds, orbital models with electrons circling a nucleus, and the equipment of the lab that studies them.
Filters
Where it sits in Science & Education
Science covers the whole field and Research the process of finding things out. Atom narrows it to structure — models of the atom, molecules, formulas — the images a chemistry or physics lesson actually draws on the board.
Formula or symbol
A skeletal formula names one specific compound and is only right for that compound; using it as a generic "chemistry" picture will look wrong to anyone who reads it. For a general science theme, the orbit model with its circling electrons is the safer choice.
Line weight on slides
Structural formulas are drawn with thin strokes on a transparent background. On a dark slide they vanish, and at small sizes the atom letters blur. Place them on light backgrounds and large enough for the heteroatoms to read.