Answer:
Half life = 7.2 seconds
Explanation:
I think it's A or D im not sure which one..
x = 5
Because 12 + 13 = 5x
25 = 5x
The discoverer of the electron was Thomson. J. J. Thomson portrayed his atom model to look like a plum pudding. In his model, he described that an atom is composed mainly of electrons stuck within a sea of positive material.
