The Periodic Table - created from Mind Map

Seite 1

History

The Modern Table

Group 1- Alkali Metals

Group 7- Halogens

Transition Metals

John Newlands created the Law of Octaves in 1864

Mendeleev 1869

Others invloved in the development were Sir William Ramsey, Rutherford and Johann Dobereiner

Similarities and Differences

He ordered the elements strictly in order of relative atomic mass

He discovered every 8th element was similar

It began to make sense- similar elements in the same group

But then he put iron in the same group as oxygen and sulphur- scientists didn't accept it

He also arranged it in relative atomic mass in groups going vertically down

How he arranged it meant there were gaps, which he figured were for undiscovered elements

By using the table, it meant he could predict properties of the elements by the atomic mass- his predictions were correct.

They both arranged it in order of atomic mass

Mendeleev left gaps

Newlands did it strcitly in order of atomic mass but Mendeleev swapped it around to make it fit better

Newlands- every 8th element was similar, Mendeleev- each group was similar

arranged by atomic number, which is used to find how many protons the element has

group 1- alkali metals

group 7- halogens

group 0/8- noble gases

2--- 3- transition metal

18 groups in total

7 periods in total

very reactive

must be stored under oil to keep away from water/air

form alkaline solutions when mixed with water

reactivity increases as you go down...

...^because the atom gets larger, the electron is lost more easily because its further from the nucleus

low melting& boiling points

low densities- some float on water

very soft- easily cut

non-metals

low melting& boiling points

when they're solid, they are brittle/breakable

poor conductors of heat/electricity

reactivity decreases as you go down...

colour gets darker as you go down

....^because the atoms gets larger, the electrons are gain less easily because it's further away from the nucleus

quite hard, dense and shiny

less reactive than alkali metals

good conductors of heat/electricity

form coloured compounds

malleable- shaped easily

usually grey and shiny except gold/silver

high melting/boiling points

only 3 are magnetic- iron, cobalt and nickel