Because attraction of water molecules around an ion depends on. that ion's density of charge, smaller ions (and thus ions of greater ionic. potenti. al) attract more water molecules. The result is the. inverse. relationship. between non-hydrated radius and hydrated radius shown below.
[v. 5] In Hebron he reigned over Judah seven years and six months: and in Jerusalem he reigned thirty and three years over all Israel and Judah.   This would have made David 37 when he became king of all Israel. Do not get confused between 'Judah' and 'Israel': they are not the same.
After this David became king over the tribe of Judah. One of Saul's sons was king over the other tribes. But when some of his own men killed him, David became king over all the Israelites. He made the city of Jerusalem the capital city. For seven years he was a king over the tribe of Judah and for thirty-three years he was the king over all the Israelites.