Y4 English Suffixes Part III

Question:
What is the rule for adding the suffix "-ation" to a root word ending in 2 consonants?
Question:
What is the rule for adding the suffix "-ation" to a root word that ends in a consonant followed by "y"?
Question:
What is the rule for adding the suffix "-ation" to a root word ending in a consonant followed by an "e"?
Question:
Are there any exceptions to the rules when adding the suffix "-ation"?