Possible or impossible?

Exercise and reference answers

Items

1. Item

   1s2 2s2 2p2

   Category

   Possible

2. Item

   1s2 2s2 2p4

   Category

   Possible

3. Item

   1s2 2s0 2p0 3s1

   Category

   Impossible

4. Item

   1s2 2s2 2p2 3s1

   Category

   Impossible

5. Item

   1s2 2s2 2p6 2d1

   Category

   Impossible

Categories

1. Item

   Possible

2. Item

   Impossible

Instructions

Tap a configuration, then the box saying whether it can exist.