{{Title text: These are all sans-serif compounds. Serif compounds are dramatically different and usually much more reactive.}}

((Capital letter H with circles on each of the legs of the H))
Hydrogen can form four bonds.  It readily bonds with itself, and often exists as a crystal.
((Image of several letters H "bonded" labeled crystalline hydrogen))

((Capital letter C with circles on each end of the letter))
Carbon can only form two bonds.  It readily bonds with hydrogen to form C₂H (mydrane) or itself.
((Image of two letters C linked labeled C₂))
((Image of two letters C linked with a letter H between them labeled C₂H))

((Capital letter O))
Oxygen is inert, forming no bonds...
((Image of several letters O labeled monatomic oxygen gas))

Typographic chemistry