Periodic Table

1. Problem

1.1. error of atom

1.2. order of elements

2. trends

2.1. atomic number

2.1.1. Sub Idea 1

2.1.2. Sub Idea 2

2.2. chemical properties

3. History

3.1. Mendeleev

3.2. published periodic tables in 1869 and 1870

3.3. Low Priority

4. Development

4.1. quantum mechanical

4.2. transuranic elements