SAN DIEGO—Clayton Richard,traded on two separated occasions by the White Sox, threw a five-hitter and the San Diego Padres swept the Cubs with a 2-0 win on Wednesday.Richard (9-11), coming off one of his better starts of the season, held the Cubs to five singles and pitched out of trouble three times to hand the Cubs their eighth straight loss.Richard struck out five, walked one and hit a batter as the Cubs had a runner reach third base three times.The Cubs scored four runs — all in Tuesday night’s 7-4 loss — and had 15 hits in the three-game series.San Diego’s runs came on Will Venable’s RBI double in the second inning and Yonder Alonso’s run-scoring single in the ninth.Richard has three career complete games and two shutouts.Jeff Samardzija (7-10) allowed one run and four hits in seven innings. He struck out five and walked two.