Spot the one that does not fit

Exercise and reference answers

Questions

1. Items

   1. Strontium
   2. Sodium
   3. Potassium
   4. Rubidium

   Odd item

   Strontium

2. Items

   1. Silvery white
   2. Soft
   3. Light
   4. Very dense

   Odd item

   Very dense

3. Items

   1. Lithium
   2. Magnesium
   3. Diagonal pair
   4. Caesium

   Odd item

   Caesium

4. Items

   1. Sodium
   2. Potassium
   3. Abundant
   4. Francium

   Odd item

   Francium

Instructions

Tap the item that does not belong with the rest.

Explanation