Until recently , there was only 2 obvious ways to categorise elements, their physical and chemical properties and there relative atomic mass.
Newlands law of octaves , every eighth element had similar properties so he listed the known elements in rows of seven.but this didn't work on the third row as the transition metals messed things up.
why was Newlands work critisied?
- because, his groups contaied elemnts that didnt have similar proerites eg, titaniuim and iron
- He mixed up metals and non metals together eg oxigen and iron
- He didn't leave and gaps for elements that had not been discovered yet.
Dmitri Memdeleev, he listed the elements in order of atomic mass (like Newland) but..... he left gaps for undiscovered elements.when new elements where discovers and they fitted the pattern it was pretty smashing
The Modern Periodic Table
The modern periodic table is based on electronic stucture. when electrons ,protons and electrons where discovered , the periodic table was arranged in order of atomic (proton) numbers.
Group 1- The Alkali Metals
As you do down group 1 the alkali metals become........
- Bigger atoms - because there's one exstra shell of electrons…