The Periodic Table Flashcards
How is it arranged
In order of atomic number( proton number) and shows all known elements
The columns are called group and elements in the same group have the same number of electrons in their outer shell so they have similar chemical properties
The rows are called periods and elements in the same period have the same number of shells
The periodic table can be split into two? What are those groups and describe each one
Metal
Shiny, conduct hear and electricity, malleable, solids. They loose electrons to form positive ions
Non metals
Dull, poor heat and electricity conductors, brittle. They gain electrons to form negative ions
How does each groups charge change when forming an ion
Group one +1
Group two +2
Group three +3
Group 4 neutral
Group five -3
Group six -2
Group seven -1
Group zero neutral
From left to right how does the periodic table go
Alkali metals, transition metals, non metals, halogens, noble gas
How did early chemists try to arrange elements and what was wrong with it ?
They arranged them by atomic weight as they didn’t know about subatomic particles and atomic number. They didn’t realise some elements hadn’t been discovered. If placed like this elements in the group wouldn’t have similar properties.
How did new land improve this
He developed the law of octaves. He said every 8th element showed similar properties so he start new rows. Only work up to calcium and some boxes had two elements.
How was menedelev improving this
He arranged elements in order of atomic weight and similar properties. He knew not all the elements had been discovered.
He reversed the order of atomic weights so some elements would fit the properties of that group.
He left gaps for undiscovered elements where he thought they belonged. He was able to predict undiscovered elements.
Why was Mendeleev table more widely approved ? Extra: what was it missing ?
It was missing nobles gasses.
But he was able to predict properties of missing elements that were discovered that filled the gaps. They match Medeleevs predictions proving his tables accuracy.
Why was the discovery of the neutron important
Made it possible to explain why the order based on atomic mass was not always right
