Bottom quark:

A bottom quark has the -1/3 charge of an electron

Name	Symbol	Mass1 (GeV)	Charge2 (e)	Generation
up	u	.002 - .005	+2/3	first
down	d	.003 - .009	-1/3	first
charm	c	1.1 - 1.4	+2/3	second
strange	s	.06 - .17	-1/3	second
top	t	163 -179	+2/3	third
bottom	b	4.1 - 4.4	-1/3	third
1 One GeV is equal to 1.78 x 10-17 kg (3.92 x 10-17 lb). 2 The charge 'e' is equal to the charge on one proton, or 1.602 x 10-19 coulombs.

Bottom quarks