3a.1 - The History of the Periodic Table Flashcards
How could the periodic table be organised in the early 1800s? (2)
- By physical and chemical properties
- Their relative atomic mass
How did Newland organise his periodic table?
Using his law of octaves
How many elements were in a row in Newland’s law of octaves?
7
When did Newland’s law of octaves break down?
On the third row
Why was Newland’s work criticised? (3)
- His groups contained elements that don’t have similar properties
- He mixed up metals and non-metals
- He didn’t leave gaps for undiscovered elements
How did Newland’s order his law of octaves?
By atomic mass
How did Mendeleev organise his periodic table?
By atomic mass
Why was Mendeleev’s table more accepted?
He left gaps that discovered elements could fill
What is the modern periodic table organised based on?
Electronic structure
What can you predict using the periodic table?
Chemical properties of elements
What holds electrons in place?
Positive charge from the nucleus
What is ‘shielding’? (2)
- The further away the electron from the nucleus the less the attraction
- The attraction becomes even less when there is lots of inner electrons as they ‘get in the way’
Why are electrons on the outer shell more likely to be lost? (2)
- Less attraction due to distance from the nucleus
- Increased shielding
Why do group 7 elements become less reactive as you go down the group? (2)
- Less attraction from the nucleus
- Shielding
What happens as you go down group 1? (2)
- More reactive
- Lower melting and boiling points
