• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Scientists and Theories of Atomic Structure

Extracts from this document...


Maryam Khan Scientists and atomic structure The structure of an atom has taken many years to develop as what we now know it to be. It consists of the hard work of many scientists, their developments and theories. Since 400BC from when the atom model was just a ball to 1913 when it became the bohr model and the atom which we now know it to be. The first of many people who played a role in this vital development of the atomic structure is the Greek philosopher Democritus with his theory of the ?atomos? meaning ?not to be cut?. Democritus was quite ahead of his time with this study and discovery. He began his research for a description of matter - Could it divided forever or is there a limit to how many times it can be divided. He later concluded that the atom was like a billiard ball that couldn?t be split any further and this is what you would end up with if you divided a sample of matter so many times and therefore was ?indivisible?. His theory stated that atoms were small, hard particles all made up of the same material however they were different shapes and sizes. He also said that these indivisible pieces (atoms) were infinite ? always moving and capable of moving together. ...read more.


Around the same time of Thomson, a lady called Marie Curie also came to the same conclusion that some atoms (at least the one she was studying) are divisible. Her contribution to the development of the atomic structure was not direct but still mattered because it was a revolutionary discovery disproving those that came before her. She discovered and isolated radium, a new element which spontaneously disintegrated into other elements- She called this process ?radioactivity?. Through continued systematic studies of the different chemical compounds gave the surprising result that the strength of the radiation didn?t depend on the compound that was being studied. Marie came to the conclusion that the ability to radiate must be linked to the interior of the atom itself as oppose to the arrangement of the atoms in a molecule. This proved that the atoms of one element at least were not indivisible and therefore disproving Dalton?s theory. However Thomson had already discovered sub-atomic particles so in all fairness Marie Curie didn?t really change anything ? she just added to this idea of atoms being divisible. Nevertheless the ?plum pudding model? was later disproved by Ernest Rutherford who is known as the ?father of nuclear physics? due to pioneering of the orbital theory of the atom with his famous much anticipated gold foil experiment. ...read more.


The negatively charged electron and the overall neutral charge of an element would mean that something balanced out the charges so there must be a positive charge within the atom. In 1918 Rutherford discovered the ?proton? whilst performing his various experiments in the field of radioactivity, bombarding nitrogen gas with alpha particles - he noticed that one of the experimental results was a flow of hydrogen. Him and others carried out a number of experiments, transmuting one atom into another by striking it with high energy ? particles and each time hydrogen nuclei were emitted. He correctly deduced that the hydrogen atoms must have come from within the nitrogen atoms themselves, which would mean that there was something within all of these atoms which was divisible, the amount of which would determine the charge of the nucleus in the atom. This integer was the number of hydrogen nuclei or ?protons? so therefore the particle Rutherford isolated was the proton. Finally, in 1932 an English physicist named James Chadwick bombarded light elements with high energy alpha particles. He found that a new type of radiation was emitted much more penetrating than any that had been detected before. He showed that this new type of radiation was made up of uncharged particles with approximately the same mass as a proton, known as neutrons. This discovery took place roughly after 20 years http://chemistry.about.com/od/historyofchemistry/p/rutherford.htm http://www.ucc.ie/academic/chem/dolchem/html/dict/atom.html http://atomictimeline.net/index.php http://www.nobelprize.org/nobel_prizes/physics/articles/curie/ http://cstl-csm.semo.edu/mcgowan/ch181/atomhist.htm http://www.physlink.com/education/askexperts/ae46.cfm ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Physical Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a star student thought of this essay

3 star(s)

Response to the question

The candidates introduction is fairly good but could still be improved, they have used background information to try and engage the reader which is a good thing as this makes it more likely that they will read all of your ...

Read full review

Response to the question

The candidates introduction is fairly good but could still be improved, they have used background information to try and engage the reader which is a good thing as this makes it more likely that they will read all of your essay rather than simply skim through it. However an introduction should also include a few sentences that introduce your topic, in this case you should say what the atom is. Finally you should state exactly what you plan to discuss so that the purpose of your essay is clear. Overall the candidates response is good and they have demonstrated a clear understanding of this topic.

Level of analysis

It is evident that the candidate has taken the time to research the history of the atom, it is important to research scientific topics as this helps to make sure that you get your facts correct. Furthermore it demonstrates an ability to work independently and it shows enthusiasm for your subject, which is always a good thing. To add to this, the candidate has sensibly included links to the online resources they have used, this is important as it shows the steps you have taken to prepare for your essay and can show that your work is not plagiarised. Unfortunately, the candidate has not concluded this essay, you should always write a conclusion, this is your opportunity to leave the reader with a good impression of your work. A good conclusion summarises key points form within you essay and states why these are important, this helps you tie together any loose ends and bring your essay to a close. You should also write a personal response, for a science based essay you could state what you have learnt from researching your topic.

Quality of writing

In general the layout of this essay is fine but I don’t recommend using bullet points, it is far better to write information in continual prose. That said, this essay is well written, the candidate links their points together nicely and there are no grammatical or spelling errors.

Did you find this review helpful? Join our team of reviewers and help other students learn

Reviewed by pictureperfect 09/08/2012

Read less
Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Physical Chemistry essays

  1. Marked by a teacher

    Heat of Neutralization. Objective: To investigate the ...

    5 star(s)

    and in the set 4 and 5, the alkali were added into the one containing the acid solution, it was because a large amount of acid or base might provide a higher degree of specific heat capacity to minimize the effects from the specific heat of the polystyrene foam cup or the thermometer.

  2. Determination of isoelectric point of protein (casein).

    increases, but the charge expressed by the carboxyl group experiences an increasing suppressive effect. As the pH level increases beyond the isoelectric point, the charge expressed by ionisation of the carboxyl group increases, but the charge expressed by the amino group experiences an increasing suppressive effect.

  1. enthalpy change

    ?H1= 52.6 x 4.2 x 1 = 220.92 J = 0.22092 KJ As enthalpy change is the standard molar enthalpy change I will need to calculate the number of moles in the substance.

  2. Identification of amino acids by using paper chromatography

    It uses liquids which may incorporate hydrophilic, insoluble molecules Column Chromatography Column chromatography uses a mobile phase to move a mixture of substances through a stationary phase. The different components of the sample have different affinities for the mobile and stationary phases, and emerge from the stationary phase at different times.

  1. AQA As Applied Science Unit 3. Colorimetry experiment on Ribena juices

    If I was to fall or anyone else was to I will call for help from a teacher, if I feel too much pain I will then go seek first aid to make sure everything is ok. I will make sure that the graph paper is used and placed appropriately to avoid any harm from occurring.

  2. Activity Series of Metals Lab

    In test number 2, a single displacement reaction was not predicted to happen due to the Activity Series of Metal. The iron would not displace the magnesium in the solutions. This will occur because magnesium has a higher placement and is more reactive on the activity series of metals than iron.

  1. Types of Chemical Reactions Lab

    The rate of decomposition of hydrogen peroxide can be increased with a catalyst, like potassium iodide, which is a substance that speeds up a chemical reaction but remains chemically unchanged at the end of the reaction. The mechanism of catalysis involves the negative iodine ions only.

  2. How does the temperature of water affect the amount of dissolved oxygen it contains?

    Pour the sample into a 500ml wide-mouth flask to be titrated. 13. Titrate the water sample against the thiosulfate solution to a pale straw colour. 14. Add a few drops of starch indicator and continue titrating to the first disappearance of the blue colour.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work