2019-07-12
Because it's a loyalty ability, Chandra's second ability isn't a mana ability. It can be activated only any time you could cast a sorcery. It uses the stack and can be responded to.
2019-07-12
Chandra's first ability affects only Elementals you control at the time it resolves. Elementals you begin to control later in the turn won't get +2/+0.