How do you write the electron configuration for the following ions?

K^+1
Br-1
Al+3
As-3?

1 Answer
Dec 21, 2017

Answer:

#K^+, Z=19; 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)#...

...the #4s^(1)# electron is lost upon ionization.....

Explanation:

#Br^-, Z=35; 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(2)4p^6#...

...the #4p# electron is FILLED upon ionization.....

#Al^(3+), Z=13; 1s^(2)2s^(2)2p^(6)#...the #3s# and #3p# electrons have been lost....

#As^(3-), Z=33; 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(2)4p^6#...and note that this configuration is the same as that of #Br^-#, i.e. isoelectronic with krypton....