ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Some Background on The Alkali Metals

Updated on October 3, 2016

The alkali metals are probably most commonly remembered by people as 'that fun bit from chemistry'. The experiments involving the first three of the alkali metals (Consisting of cutting a sliver of one of the soft metals and dropping it into a small body of water.) are likely the most visually impressive seen in high school science lessons. I feel it is only right to honour these inspiring reactants with some information on each of them.

Firstly, when we say 'alkali metals', we mean all of the elements (Excluding hydrogen sitting at the top.) on the far left of the periodic table. In order from lowest atomic mass to highest, these are: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and francium (Fr). If you chose not to pursue the field of Chemistry further than high school, you likely only recognise the first three, lithium, sodium and potassium. If you can cast your mind back to the reaction of some water and an alkali metal, you may remember that lithium wasn't very reactive, sodium was a bit more reactive, and potassium was very reactive. You will notice as you travel down the alkali metals, the reactivity of each respective metal increases. This is to do with the fact that when an alkali metal reacts with something else (In this case, water.) it loses it's outermost electron. As you travel down the periodic table, the amount of electrons of an atom increases, and thus the force of attraction exerted on the outermost electron by the nucleus decreases, making it easier to lose. For those interested, an opposite effect can be seen with halogens, as they must gain an electron.



Not to get sidetracked by the halogens, let's look at the first alkali metal; lithium. Lithium has an atomic number of 3, it has 4 neutrons and 3 protons and 3 electrons. It was discovered in 1817 by Johan August Arfwedson in Sweden. As remarked before, it is the least reactive of the alkali metals, and can even be cut with a knife! If you were to get a sample of lithium and cut it with a knife (Taking appropriate safety precautions, of course.) you would notice that the newly exposed face reacts quickly with the air, quickly turning dull. It's reaction with water is a lot more exciting, it fizzes and hisses while popping about the container. If you were to drop some universal indicator in beforehand, you'll notice the lithium leaves behind a deep purple colouring. This is actually where the alkali metals earn their name, as when they react with water they leave behind a very alkaline solution. Without a doubt lithium's most helpful use is its role in lithium-ion batteries, which hold the power of the modern world.



Next is sodium, which keeps with the alkali metal tradition in being more reactive than lithium. It has atomic number 11, with 11 protons, 11 electrons and 12 neutrons. It will turn dull faster when in contact with the air and will react more violently with water. Sodium is used just as much as lithium in daily life, in the form of salt (Or sodium chloride.), or as a coolant for some nuclear reactors when in liquid form (Between 98 and 883 degrees celsius; which admittedly seems hot for a coolant, but nuclear reactors can run a lot hotter than 93 degrees.).



Potassium is the next alkali metal, with 19 protons, 19 electrons and 20 neutrons. Potassium's reaction with water is leagues more visually awe-inspiring than the first two, reacting violently enough to ignite the hydrogen it releases during the reaction. I have a particular memory from one chemistry lesson wherein a classmate likened it to an 'atomic goldfish'. Potassium ions are essential to human life, most importantly in the transmission of signals across cells. Potassium is also a vitally important fertiliser, with crop production even doubling with the use of potassium and phosphorous based fertilisers! Like most resources on Earth, potassium is in limited concentrated supply; with some experts estimating that we may have already hit or be about to hit peak potassium/phosphorous.



Rubidium follows potassium, with 37 protons and electrons respectively and with 48 neutrons. Rubidium is so reactive that it must be stored in a petroleum jelly or else it will ignite in air. Rubidium does not play a biological role like potassium or sodium do, but it is used in the function of ultra-accurate atomic clocks. This is because a second is exactly equal to 6,834,682,610.9 (To 1 decimal place.) oscillation of the outermost electron of a rubidium atom. By counting these oscillations an atomic clock can provide extreme accuracy.



Getting into the extremely reactive range now with caesium. Caesium also has to be stored in jelly or oil and will even explode in water, in fact it has been shown with a high-speed camera to become transparent during its aggressive reaction with water.It has 55 protons, 55 electrons and 78 neutrons. Like the element above, it is also used in atomic clocks for precision time-keeping. Caesium is incredibly rare, with only around 18,000 kilograms being produced annually.



Following tradition to the extreme is francium, with an extremely large atom of 87 protons, 87 electrons and 136 neutrons. The explosion francium would produce upon contact with water would be magnitudes larger than caesium. The properties of this alkali metal aren't particularly well-documented as it is much more difficult to study than the other alkali metals, due to it being so radioactive that within at least 22 minutes half of it would have decayed. It cannot be found naturally occurring on Earth and can only be produced with incredibly expensive machinery for international research collaboration projects.



Wikipedia ;)

"The Periodic Table: A Field Guide to the Elements", by Paul Parsons and Gail Dixon (An amazing book, worth it for anyone interested in this sort of thing.)

"Encyclopedia of the Elements" By Per Enghag


    0 of 8192 characters used
    Post Comment

    No comments yet.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, 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:

    Show Details
    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 or domains, for performance and efficiency reasons. (Privacy Policy)
    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)
    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.
    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)