Besides charge and spin (1/2 for the baryons), two other quantum numbers are assigned to these particles: baryon number (B=1) and strangeness (S), which in the chart can be seen to be equal to -1 times the number of strange quarks included. ...

What particles have strangeness?

The strangeness of a particle is the sum of the strangeness of its component quarks. Of the six flavors of quarks, only the strange quark has a nonzero strangeness. The strangeness of nucleons is zero, because they only contain up and down quarks and no strange (also called sideways) quarks.

Which quark has a strangeness of?

The up and down quarks are distinguished mainly by their differing electric charges, while the heavier quarks each carry a unique quantum number related to their flavour. The strange quark has strangeness, S = −1, the charm quark has charm, C = +1, and so on.