What to Watch on Thursday: Season finales for ‘Mom,’ ‘Big Bang Theory,’ ‘Life in Pieces’

Mom (9 p.m., CBS) – In the Season 4 ender, Christy encourages Bonnie to get help from her newfound brother when she gets into trouble with the IRS. CBS comedies “Big Bang Theory” (8) and “Life in Pieces” (9:30) also end their seasons tonight. All renewed.

Riverdale (9 p.m., The CW) – In the Season 1 finale, Archie and Veronica continue to grow closer, and Betty confronts her mother. Renewed.

Chicago Med (9 p.m., NBC) – Season 2 ends as an audacious new doctor arrives at Chicago Med. Renewed.

The Catch (10 p.m., ABC) –Alice and Ben have no choice but to face their pasts in the Season 2 finale. Nothing’s for sure, but it should return.