Question

elements a. b c
mass no. 23. 20. 35
neutrons. 12. 10. 18

1)write atomic number and electric configuration of ABC

2)to which groups do abc belong

3)to which periods ABC belong

4)which is alkali,noble gas,halogen​

Answer 1

Answer:

1) atomic no. 3 electronic configuration 2,1

2) a belong to group 3. b belong to 11 c belong to 12

3) period 4

all are halogens