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Early periodic tables Dobereiner - early 1800s Triads- elements with similar properties Cl, Br, I Ca, Sr, Ba Newlands - 1865 62 known elements Law of Octaves.

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Presentation on theme: "Early periodic tables Dobereiner - early 1800s Triads- elements with similar properties Cl, Br, I Ca, Sr, Ba Newlands - 1865 62 known elements Law of Octaves."— Presentation transcript:

1 Early periodic tables Dobereiner - early 1800s Triads- elements with similar properties Cl, Br, I Ca, Sr, Ba Newlands - 1865 62 known elements Law of Octaves (every 8 th element is similar)

2 Mendeleev’s table - 1869 By atomic mass In columns Predicted missing elements

3 Moseley’s table – 1910’s Working in Rutherford’s lab Arranged by positive charge he called atomic number In rows Died in WWI

4 Periodic law When the elements are arranged by increasing atomic number, their physical and chemical properties show a repeating pattern

5 ELEMENTS Metals left side of periodic table Nonmetals right side of periodic table Metalloids along diagonal line

6 Metals Lose electrons to make + ions (cations) Conduct electricity Conduct heat Malleable Ductile React with acids Solids (except ?) Shiny

7 Nonmetals Gain electrons to form – ions (anions) Do not conduct heat Do not conduct electricity Brittle Solids, liquids or gases Do not react with acids Dull

8 Metalloids Properties of either Some gain, some lose electrons Some conduct, some don’t Some are malleable, some brittle All are solids

9 Patterns of Atomic Numbers A-6 Family NameIonValence electron Alkali metals (H) +1 1 Alkaline earth(Be) +2 2 Aluminum (B) +3 3 Carbon+/-44 Nitrogen-35 Oxygen-26 Halogen(F)-17 Noble(He)08

10 Trends Atomic radiusAtomic radius Melting pointMelting point ElectronegativityElectronegativity Oxidation number (charge on ion)Oxidation number (charge on ion)

11 Atomic radius Size of the atom Down a family atoms get bigger due to more energy levels Across a periodAcross a period atoms get smaller due to more pull by protons on electrons

12 1. Which is bigger Be or O? Why? Be 2.Which is bigger Li or K? Why? K 3.Which is smaller B or Al? Why? B 4. Which is smaller F or Cl? Why? F

13 Atomic Size Li Na K Rb Cs H Ne Ar Kr Xe Rn

14 Electronegativity the desire of an atom to steal another atoms electron Down a familyDown a family electronegativity get smaller Across a periodAcross a period electronegativity gets larger

15 Electronegativity F Cl Br I He Ne Ar Kr Xe

16 Oxidation Number Charge on the ion Metals Lose electrons – get smaller +1, +2, +3, +4 Non metals - get bigger gain electrons -3, -2, -1 -3, -2, -1

17 Oxidation Number C Si CaSrBa N P Se I

18 Melting Point Down a familyDown a family melting point gets smaller Across a periodAcross a period melting point gets larger

19 Melting Point C Si Ca SrBa HeNe Ar Kr Xe

20 What determines properties A - 7 Ionic Compounds Metal/nonmetal steal electrons +/- attraction strong High melting/boiling points Molecules Nonmetal/nonmetal share electrons Weak attraction Low melting/boiling points

21 Periodic table A-4 Mendeleev 1869 Organized elements by increasing atomic mass (weight) in columns Predicted missing elements Today’s table Organized by increasing atomic number (protons) in rows

22 1.Which has a smaller melting point N or P? P 2.Which has a smaller melting point Na or Mg? Mg 3.If the melting point of Si is o C and S is o C what would you expect the melting point of P to be?

23 Octet Rule An atom will gain or lose electron to have an octet (or filled) valence energy level


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