Periodic Table

1. Development

1.1. quantum mechanical

1.2. transuranic elements

2. History

2.1. Mendeleev

2.2. published periodic tables in 1869 and 1870

2.3. Low Priority

3. Problem

3.1. error of atom

3.2. order of elements

4. trends

4.1. atomic number

4.1.1. Sub Idea 1

4.1.2. Sub Idea 2

4.2. chemical properties