Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Soraka is viewed as the healing champion that can easily be killed if she is focused. This build allows you to still heal without so much fear of being killed. You might even get a kill or two with this Soraka build.
Very high mana and mana regen so you can stay out and cast your spells all day long
Good movement speed
Good ability power along with fairly high armor
Low attack damage and attack speed but your playing Soraka you cant have expected much here
Low magic resist