Monday, 26 March 2012

The Periodic Table


Specification:
  • Understand the terms group and period
  • Recall the positions of metals and non-metals in the Periodic Table
  • Explain the classification of elements as metals or non-metals on the basis of their electrical conductivity and the acid-base character of their oxides
  • Understand why elements in the same group of the Periodic Table have similar chemical properties
  • Recall the noble gases (group 0) as a family of inert gases and explain the lack of reactivity in terms of their electronic configuration

Notes:
  • The periodic table is a list of elements arranged in order of their increasing atomic (proton) number.
  • A period is a horizontal row of elements--the number of electron shells is the same as the period number of the element.
  • A group is a vertical column of elements--the number of valence electrons (outer shell electrons) is the same as the group number of the element.
    • Since elements with similar electronic configurations have similar chemical properties, we can deduce that elements in the same group have similar chemical properties.
  • The block of metals between Groups 2 and 3 are known as the transition elements/metals, these form coloured compounds.

     
Chemical Properties

Metals
Non-metals
  • Usually have 1-3 electrons in their outer shell
  • Lose their valence electrons easily
  • Form oxides that are basic
  • Are good reducing agents

  • Usually have 4-8 electrons in their outer shell
  • Gain or share valence electrons
  • Form oxides that are acidic
  • Are good oxidizing agents

Physical Properties

Metals
Non-metals
  • Good electrical and heat conductors
  • Malleable—can be hit and shaped
  • Ductile—can be stretched into wire
  • Possess metallic luster (shiny)
  • Opaque as thin sheet
  • Solid at room temperature (except Mercury [Hg]- liquid)

  • Poor conductors of heat and electricity
  • Brittle- if a solid
  • Non-ductile
  • Do not possess metallic luster
  • Transparent as a thin sheet
  • Solids, liquids or gases at room temperature


 

Noble Gases (Group 0):
  • Least reactive elements in the periodic table.
  • Apart from helium (which has 2), the rest have 8 valence electrons--all have full outer shells.
  • Their full electronic structures make them unreactive.
  • Group 0 elements also referred to as inert gases (because they are unreactive) or rare gases (because less than 1% of the air is made up of these gases).
  • Noble gases do not react to form compounds because their atoms have full outer shells of electrons, it is energetically easier to stay as they are. 
     
    The noble gases are:
  • Monatomic elements
  • All colorless gases at room temperature
  • Have low melting and boiling points that increase going down the group (As atoms get bigger, there is greater intermolecular attraction that require more energy to break.)
  • Insoluble in water
  • Unreactive
just thought this was cool :P 

17 comments:

  1. can u post stuff on physical chemistry section 4? tank u

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  2. Hey look at the 'Acids, alkalis and salts' post. What else from Section 4 do you need? I have other bits and pieces from it in other posts..get back to me if you still don't understand smth though. :)

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  3. dont understand how the polymers of alkenes and alkanes work! draw the displayed formulas for that as well!

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  4. see the 'polymer' post, hope it makes sense now. but i'm not sure if you're confused about alkanes/alkenes and their displayed formula, or addition polymerisation and the polymers. :S could you clarify if my new post didn't help?

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  5. addition polymerisation cunfuzzles me!

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  6. thank u so much! this is awesome! :)

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  7. hey michelle what about the sections
    Group 7 elements — chlorine, bromine and iodine
    and Oxygen and oxides? i would really appriciate it if u could do them becuase they r in my periodic table syllabus :)

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  8. can u post stuffs on the trends,physical and chemical properties of group 1 elements...

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    Replies
    1. Hey sorry this is so late, I've been away on summer. Anyways, I've just updated the following post to include more detail about the Group 1 elements. http://askmichellechemistry.blogspot.com/2012/05/group-1-elements-lithium-sodium-and.html
      :)

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  9. Thank you for all your help its really helped with tests :)

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  10. This whole website saved my life thank you so much for taking the time to produce these amazing notes <3

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  11. Hey guys, although this blog is helpful, it is only good for double science...if you want triple science stuff, look at this amazing blog--> http://hannahhelpchemistry.blogspot.co.uk/
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Note: This blog will no longer be updated as I finished IGCSEs in 2012. Sorry! :( If you are interested in buying IB notes though, please contact me. :)