The following table summarizes the key properties of the six quarks. Flavor quantum numbers (isospin (I3), charm (C), strangeness (S, not to be confused with spin), topness (T), and bottomness (B′)) are assigned to certain quark flavors, and denote qualities of quark-based systems and hadrons. The baryon number (B) is +​13 for all quarks, as baryons are made of three quarks. For antiquarks, the electric charge (Q) and all flavor quantum numbers (B, I3, C, S, T, and B′) are of opposite sign. Mass and total angular momentum (J; equal to spin for point particles) do not change sign for the antiquarks.

Quark flavor properties[78]
Particle Mass (MeV/c2)* J B Q (e) I3 C S T B′ Antiparticle
Name Symbol Name Symbol
First generation
up
u
2.3±0.7 ± 0.5 12 +​13 +​23 +​12 0 0 0 0 antiup
u
down
d
4.8±0.5 ± 0.3 12 +​13 −​13 −​12 0 0 0 0 antidown
d
Second generation
charm
c
1275±25 12 +​13 +​23 0 +1 0 0 0 anticharm
c
strange
s
95±5 12 +​13 −​13 0 0 −1 0 0 antistrange
s
Third generation
top
t
173210±510 ± 710 12 +​13 +​23 0 0 0 +1 0 antitop
t
bottom
b
4180±30 12 +​13 −​13 0 0 0 0 −1 antibottom
b
J = total angular momentum, B = baryon number, Q = electric charge, I3 = isospin, C = charm, S = strangeness, T = topness, B′ = bottomness.
* Notation such as 173210±510 ± 710 denotes two types of measurement uncertainty. In the case of the top quark, the first uncertainty is statistical in nature, and the second is systematic.