Chemistry - Tripple Flashcards
How did John Dalton arrange the table?
Arranged elements in order of their atomic mass
Who created the first periodic table in 1808?
John Dalton
Who created the periodic table in 1864?
John Newlands
How did John Newlands arrange his periodic table?
Built on John Daltons idea and came up with the idea of the “law of octaves” every eighth element had similar properties so he arranged them into rows of 7
Why was John Newlands table criticised?
Left no gaps- elements were still being discovered
Only worked up till calcium
His groups didn’t contain similar properties
He mixed metals and non-metals
Who came up with the periodic table in 1869?
Dmitri Mendeleev
How did Dimitri arrange the table?
Put elements in order of their atomic mass but left gaps this predicted new elements
Put the elements in vertical columns (groups) these were the similar properties
How is the modern periodic table arranged?
Arranged in order of their atomic proton number, the group number tells us the number of electrons in the outermost shell and therefore how it reacts
How does shielding work?
The further away from the nucleus the lest attracted the electron is to the nucleus
The more electrons in the inner shells the more shielded it is so the attraction is even less
Why do group 1 metals get more reactive as they go down the group?
As you go down the group the larger the atom is therefore the less attracted the electron is in the outermost shell due to distance and shielding this means the electron is more easily lost
Why do group 7 elements get less reactive going down the group?
The atoms get larger as you go down the group therefore there is increased distance and shielding this means that the outer shell is less likely to gain and electron
Name the properties of the group 1 alkali metals
Go down more reactive and have a lower melting and boiling point
Low density
Have 1 electron in outer shell making it very reactive
Form ionic compounds with non-metals as they are keen to lose an electron
Squeaky pop
Produces hydrogen and hydroxide
Name the properties of the group 7 halogens
As they go down they are Less reactive Higher melting points Higher boiling points - more reactive halogens will displace less reactive halogens
What is the properties of fluorine?
Very reactive and has a yellow gas
What is the properties of chlorine?
Fairly reactive and a dense green gas
What are the properties of bromine?
Dense and poisonous and red/brown volatile liquid
