Topic 1b- Development of the periodic table (Paper 1 + 2)

Question 1

Who rediscovered the idea of elements in the early 1800s?

Answer 1

John Dalton.

Question 2

Who built on Dalton’s ideas and what did they do?

Answer 2

Newlands created a table with “octaves.” He noticed the properties of every eighth element seemed similar, so his table had ascending order of mass in rows of eight.

Question 3

Who was Mendeleev and what was different about his table?

Answer 3

He left gaps for undiscovered elements and made predictions about their properties.
He reordered some of the elements because he believed they had been measured incorrectly.

Question 4

What are three important differences between Mendeleev’s table and the modern periodic table?

Answer 4

1. Modern periodic table is ordered using atomic number, Mendeleev used atomic mass.
2. Modern periodic table contains many more elements than Mendeleev’s.
3. No gaps in modern periodic table.