A prophet is one who shows the right path. Imam is one who takes you to the right path. This is the reason on the day of judgment all of humanity will be called with their Imams and not prophets. Allah has mentioned this in Sura Bani Israel ayah 71: "Remember that day when all of humanity will be called with their Imams."
It is very important people recognize that Imam which is from Allah. If he chooses a false imam, then he will remain in jahannum for all of eternity. This is why RasoolAllah (saw) said, " One who dies without recognizing his Imam (who is from Allah) dies the death of jahil (ignorant), kafir (disbeliever), and nifaq (hypocrite)."
The number of Imams (as) has been twelve from the beginning until the end. In Arabic twelve is called ithna ashari. This is why we call ourselves Ithna Ashari (believers of twelve Imams as). No one can increase or decrease from the number of twelve. Anyone who does this is out of the Shia religion.
Here are the sacred names of the twelve Imams (as). You must always remember Them.
First imam: Ameerul Momineen Ali (as) ibn Abi Talib (as)
Second imam: Imam Hasan (as) bin Ali (as)
T hird imam: Imam Hussain (as) bin Ali (as)
Fourth imam: Imam Ali (as) bin Hussain ( as) (Zainul Abideen)
Fifth imam: Imam Muhammad (as) bin Ali (as) (Baqir)
Sixth imam: Imam Jafar (as) bin Muhammad (as) (Sadiq)
Seventh imam: Imam Musa (as) bin Jafar (as) (Kazim)
Eighth imam: Imam Ali (as) bin Musa (as) (Reza)
Ninth imam: Imam Muhammad (as) bin Ali (as) (Taqi)
Tenth imam: Imam Ali (as) bin Muhammad (as) (Naqi)
Eleventh imam: Imam Hasan (as) bin Ali (as) ( Askari)
