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Ms. Reynolds

MacArthur High School: (516) 434-7225

Ms. Reynolds

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Periodic Table

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Periodic Table
​​​
Periodic Table of Elements

Foundations
Lesson 1

Classifying Elements
  • 1829 Dobereiner’s Triads
  • 1864 Newland's Octaves
  • 1869 Mendeleev – arranged table by Atomic Mass
  • 1913 Moseley: Modern Table – arranged table by Atomic Number
Atomic number represents the number of protons in an atom.


Arrangement of the Periodic Table

Columns (across the top): 
Columns are called groups
Each element in a column will have the same number of valence electrons; similar chemical properties 

Rows (down the side):
Rows are called periods
Each element in a row will have the same number of shells (principle energy levels)


Group Names
1: Alkali Metals: very reactive (1 valence electron)
2: Alkaline Earth Metals(2 valence electrons)
3-11:Transition Metals: ions in colored solutions
17: Halogens: (7 valence electrons)
18:Noble Gases: Complete outer shell -non reactive (Monomers)



Types of Elements
Lesson 2

MetalsFound on the  left side of the PT 
Properties:
  • malleable (can be hammered into sheets)
  • ductile (can be drawn into wires)
  • shiny (have luster)
  • good conductors of heat and electricity
  • high melting and boiling points
  • DONATE electrons when bonding

NonmetalsFound on the right side of the PT
Properties:
  • dull (lack luster)
  • brittle (can break easily)
  • poor conductors of heat and electricity
  • low melting and boiling points
  • ACCEPT electrons when bonding

MetalloidsFound on the “staircase” of the periodic table
Properties:
  • behave as both metals and nonmetals
There are two exceptions:  Al & Po



Atoms vs Ions
Lesson 3

Review:
AtomsNeutral particles because #p = #e (as written on PT)
Ionscharged particles because #p do not = #e

Octet Rule: Every element wants a noble gas configuration (complete outer shell). They will lose or gain valence electrons to do so. 

Metals
  • have 1 or 2 valence electrons
  • Lose electrons to form POSITIVE ion (ca+ion)
  • lose e- get smaller
  • Radius atomic>ionic

Nonmetals
  • have 6 or 7 valence electrons
  • Gain electrons to form NEGATIVE ion (anion)
  • gain e- get bigger
  • Radius atomic<ionic

Cation Example:​ Lithium
​        atom                                       ion




Anion Example:        Fluorine
       atom                                       ion





Determine the number of protons and electrons in each of the following atoms, then identify the ions by including the number of protons and electrons.

Ex:
Mg atom Mg ion   p+                 p+
        e- e-
Config



Ca atom Ca ion Ca will form a ________



Br atom Br ion Br will form a _________




O atom O ion O will form a ________



K atom K ion         K will form a ________



Electron Dot Diagrams (Lewis Dot)
Lesson 4
  • ​Used to represent the valence electrons of an element. 
  • The symbol is the “Kernel” and represents the nucleus and all non-valence electrons.​

C                                  Br                          Na



Dot Diagrams Atoms vs Ions

Atom                                            Ion

  Li            


  Ca


  F


  O



Trends of the Periodic Table
Lesson 5

Atomic Radius
Trends can be found on Table S
Trend from left to right (across a period) =  DECREASES
Trend from top to bottom (down a group) =  INCREASES

Ionic Radius
No table
An atom that has gained or lost electrons will change in atomic size
Metals lose electrons so ionic radius < atomic radius.
Nonmetals gain electrons so ionic radius >atomic radius.

Ionization Energy
The amount of energy required to remove the most loosely held valence electrons from a neutral atom.
Trends can be found on Table S
Trend from left to right (across a period) = INCREASES
Trend from top to bottom (down a group) = DECREASES

Electronegativity (Electron Affinity)
The measure of attraction an atom has for a pair of electrons
Trends can be found on Table S
Trend from left to right (within a period) = INCREASES
Trend from top to bottom (within a group) = DECREASES 

Reactivity
The transfer (gain or lose) of electrons
*think about what elements want to do…

Metals: more active toward the bottom left corner (Fr).
Nonmetals: more active toward the upper right corner (F).
Noble gases have no reactivity - why they weren't discovered for many years (monomers).