The periodic properties of the elements
Sponsored Links
This presentation is the property of its rightful owner.
1 / 30

The Periodic Properties of the Elements PowerPoint PPT Presentation


  • 44 Views
  • Uploaded on
  • Presentation posted in: General

The Periodic Properties of the Elements. By Lauren Querido, Chris Via, Maggie Dang, Jae Lee. The Founders of the Periodic Table. Luthar Meyer. Dmitri Mendeleev. http://nuclphys.sinp.msu.ru/persons/images/mendeleev.gif.

Download Presentation

The Periodic Properties of the Elements

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


The Periodic Properties of the Elements

By Lauren Querido, Chris Via, Maggie Dang, Jae Lee


The Founders of the Periodic Table

Luthar Meyer

Dmitri Mendeleev

http://nuclphys.sinp.msu.ru/persons/images/mendeleev.gif

http://chemheritage.org/classroom/chemach/images/lgfotos/04periodic/meyer-mendeleev2.jpg


7.1 Developing the Periodic Table

  • Dmitri Mendeleev (1869)- and Luthar Meyer Published very similar documents to classify the elements. And were the first to make the modern periodic table

    • Used chemical and physical properties to classify

  • Henry Moseley (1887-1915)- Developed concept of atomic numbers

    • Found that frequency increases as the atomic mass increases


7.2 Electron Shells and Size of Atoms

  • Electron Shells in Atoms

    • Gilbert N. Lewis – electrons are arranged in shells surrounding the nucleus.

  • Atomic sizes-http://grandinetti.org/Teaching/Chem121/Lectures/PeriodicTrends/assets/radiitable.gif


  • Bonding Atomic Radius- the distance between the center of two bonding atoms

http://www.chembook.co.uk/fig13-1.jpg


Practice Problem #1

  • Predict the lengths of C-S, C-H, and S-H bonds in this molecule

  • Radius of C = 0.77 Å

  • Radius of S = 1.02 Å

  • Radius of H = 0.37 Å

  • When determining the bonding radius, you add the radius of the bonding atoms together


Answer to Practice Problem #1

  • C-S bond length = radius of C + radius of

    = 0.77 Å + 1.02 Å = 1.79 Å

  • C-H bond length = 0.77 Å + 0.37 Å = 1.14 Å

  • S-H bond length = 1.02 Å +0.37 Å = 1.39 Å


7.2 continued

  • When moving across a row, the number of core electrons stay the same but the nuclear charge increases

  • The effective nuclear charge increases even though the quantum number remains the same

  • Shielding is the process of blocking the protons effective charge on the outermost electrons


7.3 Ionization Energy

  • Ionization Energy – to remove an electron from the ground state

  • Second Ionization – removing the 2nd electron from the ground state

  • I1<I2<I3 and so forth; It increases in magnitude

  • The greater effective nuclear charge, the greater the ionization energy


7.3 cont..

  • There is a sharp increase in ionization energy when an inner shell electron is removed

  • Periodic Trends

  • Within each row, the ionization energy increases with atomic number

  • Within a group, the ionization energy generally decreases with increasing atomic number


7.3 cont..

3. The ionization energy of transition elements & f-block metals increase slowly as you read from left to right.

  • The transition in ionization energy are affected by how strong an electron is attracted to an atom

  • It is affected by the effective nuclear charge and the average distance from the nucleus.


7.3

  • The irregularities are explained through the periodic table

  • Electrons in the s orbital are more effective at shielding than in the p orbital


7.4 Electron Affinities

  • Positive ionization energy = energy put into atom in order to remove electrons

  • Electron affinity = attraction of change in energy when the electron is added

  • Most atoms = energy is released when electron is added

  • A positive electron affinity, an ion will not form


7.4 cont..

  • On the periodic table, electron affinity becomes negative towards halogen (closest to being stable)

  • The electron affinity does not change when they move down a group (noble gases)


http://www.meta-synthesis.com/webbook/35_pt/best_PT-form.jpg


Element Classificationhttp://www.elementsdatabase.com/Images/periodic_table1.gif


7.5 Metals, Nonmetals, and Metalloids

  • Metals

    • Tend to have low ionization energies and lose electrons when they undergo chemical reaction

    • Most metal oxides are basic oxides that dissolve in water react to for metal hydroxides

      Metal Oxide + Water  Metal Hydroxide

    • Metal oxides show their basicity by reacting with acids to form water and salts

      Metal Oxide + Acid  Salt + Water


7.5

  • Characteristics of Metals

    • Have a shiny luster

    • Various colors

    • Solids are malleable and ductile

    • Good conductors of heat and electricity

    • Most metal oxides are ionic solids that are basic


7.5

  • Nonmetals

    • Tend to gain electrons and become anions

      Metal + Nonmetal  Salt

    • Most nonmetal oxides are acidic oxides that dissolve in water react to form acids

      Nonmetal Oxide + Water  Acid

    • The acidity of nonmetal oxides is shown by the fact they dissolve in basic solutions to form salts

      Nonmetal Oxide+ Base  Salt + Water


7.5

  • Characteristics of Nonmetals

    • Do not have a luster

    • Various colors

    • Solids are usually brittle; some are hard, and some are soft

    • Poor conductors of heat and electricity

    • Most nonmetallic oxides are molecular substances that form acidic solutions


7.5

  • Metalloids

    • Have properties intermediate between nonmetals and metals

http://www.rkm.com.au/METALLOIDS/metalloid-images/METALLOID-SILICON-500.jpg


7.6 Group Trends for the Active Metals

  • Group 1A: The Alkali Metals (most active)

    • Metallic Characteristics

      • Silvery

      • Metallic luster & high thermal

      • Electrical conductivities

      • Have low densities & melting points

      • Very reactive b/c they want to lose 1 electron to form ions with a 1+ charge so it becomes more stable


7.6 cont..

  • As you move down a group

    • Atomic radius increases

    • 1st ionization energy decreases


7.6 cont..

  • Group 2A: The Alkaline Earth Metals

    • Properties of Alkaline Earth Metals

      • Harder

      • More Dense

      • Melt at higher temps

      • Highly Reactive

    • Compared to alkali Metals, Alkaline Earth metals..

      • Have lower 1st ionization energies

      • Are less reactive


7.7

  • Group 6A

  • Oxygen is a colorless gas at room temperature while all the other elements in this group are solid.

  • Oxygen has two main forms: 02=“oxygen” and 03=“ozone”.

  • This is an example of an allotrope, it has different forms of the same element.


7.7

  • The most stable form of sulfur is S8, It is a yellow solid.

  • All of the elements in this group have the tendency to gain electrons form other elements.

  • http://www.science.uwaterloo.ca/~cchieh/cact/fig/s8.gif


7.7

  • Group 7A: Halogens

  • Halogens is named Greek words, “halos” and “gennao” meaning salt formers.

  • Fluorine and Chlorine are gases, bromine is a liquid, and iodine is a solid at room temperature.

  • These elements melting and boiling points increase with atomic number.

  • These elements have highly negative electron affinities because they have the need to gain electrons from other elements.


The Fluorine atom is very reactive!

http://www.chemistryland.com/ElementarySchool/BuildingBlocks/FluorineAttracts.jpg


7.7

  • Group 8A: Noble Gases

  • All of the elements are nonmetals at room temperature and they are monatomic

  • They are very unreactive because they have completely filled s and p orbitals.

  • They also have very large 1st ionization energies.


That’s All Folks


  • Login