ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

A brief look at the history of the atom

Updated on September 20, 2011

If you break a piece of matter in half, and then break it in half again, how many breaks will you have to make before you can break it no further? This is the question Democritus, a Greek philosopher, asked back in 460 B.C. He thought that there must be a smallest bit of matter. So Democritus called these particles of basic matter atoms.

Due to no other Greek philosophers taking it up and being interested in what Democritus had discovered, it was then more than 2000 years before anyone decided to carry on and explore this matter. It then wasn’t until the start of the 19th century, that John Dalton, an English chemist, put forward his ideas to do with atoms. From Dalton’s observations and experiments he believed that atoms were like tiny hard balls. In chemical reactions he also discovered that the atoms would combine with other atoms and rearrange themselves.
He said that all matter is composed of atoms, along with each chemical element having it’s own atoms that differed from each other in mass. With Darlton also finding out many other rules about atoms.

J.J Thomson's 'Plum pudding' model
J.J Thomson's 'Plum pudding' model

J.J Thompson

Then during the 19th century Thomson discovered electrons, this negatively charged particle turned out to be much smaller than any atom, as it would take 2000 electrons to weigh the same as the lightest element hydrogen.Thomson knew that electrons had a negative charge and thought that matter must have a positive charge. So he made a model of an atom called ‘plum pudding’ model, as it looks like pudding with raisins stuck in it. His model shows the negative electrons and positive matter, which he discovered.

Rutherford's atom
Rutherford's atom

Ernest Rutherford


Unexpectedly in 1911, Rutherford’s results became interesting when he bombarded atoms with alpha rays. He shined them onto atoms of gold foil and found that some particles bounced off the foil and back in a different direction and some going straight through the foil. Rutherford then concluded and thought that like the planets in our solar system the electrons must be orbiting around the dense nucleus, which is the centre of the atom. He found that the nucleus had a positive charge with the negatively charged electrons orbiting around the outside.

Niels Bohr diagram
Niels Bohr diagram

Niels Bohr

In 1914 Bohr came up with the next big discovery and came up with two big important rules:

  • Electrons can orbit only at certain allowed distances from the nucleus.
  • Atoms radiate energy when an electron jumps from a higher-energy orbit to a lower-energy orbit. Also, an atom absorbs energy when an electron gets boosted from a low-energy orbit to a high-energy orbit.


He then quoted ‘ that these rules seem impossible, but they describe the atoms operate. So lets pretend they are correct and use them.’

With no one being able to explain after some time of knowing that the light given out when atoms were heated always had specific amounts of energy, Bohr suggested that the electrons must be orbiting the nucleus in different energy levels called shells (As shown in diagram).This energy must be given out when 'excited' electrons fall from a high energy level to a low one.

Still today we use the these theories stated from these scientists and has been greatly investigated over the past two centuries and still investigated to this day.

Below is a cool video I found which is worth checking out showing you how sodium reacts when mixed with water!

Exploding sodium

Comments

    0 of 8192 characters used
    Post Comment

    • marstoblog profile imageAUTHOR

      marstoblog 

      6 years ago from Hitchin, England

      thank you I'm glad you learn't something!

    • point2make profile image

      point2make 

      6 years ago

      An interesting look at the history of the atom. I enjoyed your hub and learned a few things as well. Thanks

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)