Arbuckle Island
No.
Yes it is!
St. Kitts and Nevins is a island nation and part of the Commonwealth of Nations.
By ratifying the US Constitution.
We don't know the island you ask about. We need a name.
Yes, Staten Island is part of New York City.
Peru
Puerto Rico.
Rhode Island is the smallest state in the US, but it is not an island. There is a mainland but there also are islands which are part of the state, some of them small, and some not very small at all.
Rhode island was to little for an independence and since they were closest to US they decided to integrate
It became a US State on 29 May 1790.