Find the bad digit in each setup

Exercise and reference answers

Questions

1. Statement parts

   1. Sodium
   2. (11)
   3. :
   4. 2
   5. ,
   6. 8
   7. ,
   8. 2

   Correction

   Sodium has 11 electrons. Correct configuration is 2, 8, 1.

   Incorrect part

   2

2. Statement parts

   1. Argon
   2. (18)
   3. :
   4. 2
   5. ,
   6. 8
   7. ,
   8. 10

   Correction

   Argon has 18 electrons. Correct configuration is 2, 8, 8.

   Incorrect part

   10

3. Statement parts

   1. Calcium
   2. (20)
   3. :
   4. 2
   5. ,
   6. 8
   7. ,
   8. 8
   9. ,
   10. 4

   Correction

   Calcium has 20 electrons. Correct configuration is 2, 8, 8, 2.

   Incorrect part

   4

Instructions

Each line shows how electrons sit in an atom's shells. Tap the digit that does not fit.