What were the two reason why Newlands ideas about the periodic table weren't accepted by other scientists ???
- 0 votes
AQA Unit 3
These questions about mendeleev and Newlands keep popping up in past papers, and i really want to get some bullet point reasons with which i can answer these types of questions straight away. This would be really useful because i've got my exam next week
- 12 votes
There are 4 reasons.
1) His groups contained elements that didn't have similar properties
2) He mixed up metals and non-metals
3) He didn't leave any gaps for elements that hadn't been discovered yet even though scientists knew there were more to discover.
4) The pattern broke down after the 3rd row where transitions metals messed it up.
- 1 vote
Newlands proposed a new order of discovered elements based on his octave theory (that elements occured with regular properties in groups of 8).
Musical scales I hear you ask? Thats what the 'real' scientists in his day said. Reason #1
He also proposed that elements with very different properties could go together - dont say he mixed them up because he didn't (this implies that he didnt know what he was doing!). He actually placed metals and non-metals in the same groups/columns (remember - his groups and periods were the opposite way around to those in the modern periodic table) AND he placed very reactive elements with unreactive ones e.g. Copper and rubidium! Reason #2
Dont forget about the pairs of elements occupying one box! e.g. Co & Ni Reason #3
This table was formed in 1864 - before Mendeleev put his together, but Newlands didnt leave spaces - you cant criticise him for not thinking there were still elements out there!
Unfortunately he wasnt well know or respected in the scientific community so his ideas were too new, too radical to be accepted at the time. Reason #4
Yes its true that they didnt know about protons and neutrons but how can this be a reason people back then didnt accept his ideas?! You cant say evaluate someones theory by todays standards based on peoples understanding back then - they didnt know how close it was to being right!
- 0 votes
Newlands proposed his 'law of octaves'. So he put the 56 known elements back then into 7 different groups. This wasn't accepted because:
- The properties of the elements did not match very will with the other elements in the group, hence other scientists did not accept his ideas.
- Scientists at that time (19th Century) knew nothing about protons and electrons, so all of his 'law of octaves' was based only on the atomic weights, this meant it was a very difficult concept to prove.
That's it really, normally 1 or 2 mark question so this should be enough.
- 0 votes
an easier was is that: mixed non metals and metals
and heDID NOT LEAVE ANY GAPS
they always work :)
- 0 votes
ahh okay good stuff, cheers guys
Good luck next week x