Your build is right, but your are place some wrong information, because this is ARAM.

You do never buy the Tear of the Goddess, you first buy would be the Chalice of Harmony and one thing more you never buy earlier 'power ups' for boots if you haven't yet all your items.

This is the right order Chalice of Harmony > Boots > if enough kills for Needlessly Large Rod then Rabadon's Deathcap if not then go for parts for Athene's Unholy Grail or for 1200g parts for Rod of Ages.

And by masteries you need to put the points in utility in defence

End items

Athene's Unholy Grail/+(which first is your choice)/ Rod of Ages - Sorcerer's Shoes - Rabadon's Deathcap - Void Staff/ Liandry's Torment + Morellonomicon

Why Morellonomicon because the CC reduction, choose Void Staff if your enemy build a high MGR.

Athene's Unholy Grail + Rod of Ages is better then + Archangel's Staff > Seraph's Embrace + Athene's Unholy Grail

Because you get by Athene's Unholy Grail if you by buy first, mana regeneration of assist and MGR+CDD, by Rod of Ages you will get regeneration when you get level up + stacks 80AB,

by a Archangel's Staff your are missing the extra mana and health if you compare to Rod of Ages.