In our Bibles today we have 1 and 2 Chronicles as two books but they were originally one book. The Book of 1 Chronicles is a book of narrative history, and genealogies. While the books of 1 and 2 Kings focus on the northern kingdom, Israel, 1 Chronicles focuses on the southern kingdom, Judah. Nothing is said about the northern kingdom in 2 Chronicles because Jeroboam led the northern tribes after sins that took them away from worshipping God.
For this reason, 1 Chronicles focuses on the kings and events that relate to the southern kingdom, specifically the tribe of Judah. 2 Chronicles covers the history of both 1 and 2 Kings. The purpose of the book was to encourage the remnant that had come out of the Babylonian captivity and it covers in some extra detail most of the information already covered by 1 and 2 Samuel and 1 and 2 Kings.
Here You Will Find The Complete Study Of 2 Chronicles