Almost right. Brontosaurus is no longer a valid name, being the same animal as Apatosaurus.
Brachiosaurus us is valid dinosaur name.
Both Apatosaurus & Brachiosaurus are sauropods - huge quadrupedal dinosaurs with long necks and tails + small heads.
Interestingly, both Apatosaurus & Brontosaurus were names given to fossil remains by the same man - Prof Marsh. Back in the late 19th century, at the height of the 'bone wars' when Marsh & his rival Cope were pulling as many dinosaurs out of the ground in an attempt to out do each other.