Type the number

Exercise and reference answers

Questions

1. Answer

   3

   Question

   Elements in one Dobereiner triad

2. Answer

   3

   Question

   Triads Dobereiner could identify

3. Answer

   56

   Question

   Elements Newlands assumed existed

4. Answer

   18

   Question

   Groups in the Modern Periodic Table

5. Answer

   1913

   Question

   Year Moseley gave the atomic number

6. Answer

   37

   Question

   Atomic radius of hydrogen in picometres

Instructions

Type the number only.

Explanation