Gemma Stokes Unit 1 P1

The Periodic Table

Introduction

The History of the periodic table reflects over a century of growth in trying to understand chemical properties in the early 19th century,scientists first began to find ways to classify the elements.One of the first attempts to classify the elemts was carried out by a German Chemist called Johann Dobereiner in 1817.This chemist Johann Dobereiner realised that the properties of calcium,barium and strontium are actually very similar.Dobereiner also then began to notice that the atomic mass of strontium was in the middle between those of calcium and barium.After making this discovery he then decided to group these three elements into what was called a triad.

Later on Dobereiner also discovered several other similar groups of three elements which had similar properties.In each of these cases it was also noticed that the middle element has an atomic mass,which is halfway between the first anf the third elements in the Triad.However John Doberereiners ideas were not taken seriously by any other people.

The peridoic table itself is actually a visual representation of the periodic law,This law states that certian properties of the elements are repeated periodically,once they have been arranged by their atomic mass number.The elements in the table are arranged into vertical columns (groups) and rows (horizontally).

Below is a recent picture of the modern Periodic Table:

Atomic Structure

Atoms are particles of elements.They are made up of three types of particles these are: Electrons ,Protons ,Neutrons .Each of these particles which atoms are made up of each have different properties.Electrons are very tiny and very light and they have a negative electrical charge (-).Where as Protons are larger and and a lot heavier and they have the opposite charge to what a proton has.Neutrons are large similar to protons and they are also havy similar to protons.But Neutrons do not have any electrical charge.
Join now!


Atoms are the most smallest particles found in ordinary substances,and these can usully join together to to form molecules.Hydrogen has the smallest atoms,which is made up of 1 single proton and a single electron orbiting it.An atom of Hydrogen has 1 proton,no neutrons and 1 electron.It has a zero charge because it has the same number of electrons and protons.

Isotopes

Each of the elements has its own atomic number.Therefore this means that all the atoms of any specific element must have the same number or protons and electrons.Therefore this means that any atom of Hydrogen ...

This is a preview of the whole essay