Kimikoom5672 Kimikoom5672 13-12-2022 Chemistry contestada Consider the two electron arrangements for neutral atoms a and b. What is the atomic number of a? a - 1s 2 , 2s 2 , 2p 6 , 3s 1 b - 1s 2 , 2s 2 , 2p 6 , 5s 1.