1. Ch 4 The periodic table Element organizations:
Patterns in element properties, groups of elements that share properties

2. Contribution to the periodic table
John Newland
Arranged elements by properties and increase atomic mass.
Rows of similar chemical and physical properties repeated every 8th element.
law of octaves.

3. Contribution to the periodic table
Dmitric Mendeleev:
63 elements in a table to show similarities & periodic trends by increase atomic mass.
Chemical & physical properties w/ symbols of each element on cards.
Gaps in table, predicted properties of missing elements (Ga, Sc & Ge)
Not all fit by increasing atomic mass (Te & I), needed to switch but did not understand why.

4. Periodic law Mosley: Identified element & atomic number.
Arrange elements by increasing atomic number, fix some of the problems with Mendeleev’s PT
Ramsey:
Discovered noble gases
Periodic law:
Repeating physical & chemical properties of elements change periodically with their atomic number.
Periodic law

5. Periodic table organization (pg 120-121)
Groups:
Vertical column of elements in the periodic table.
Elements share chemical & physical properties, same number valance elements.
By element’s valence electrons (outer most electrons) determines chemical properties
s and p block electrons
Periods:
Horizontal row (same # of occupied energy levels
Period # = occupied energy level
Systematic change properties (metal -> nonmetal)

6. Section 2: Tour of the P.T. Metals, Nonmetals & Mettalloids
Metals: (most elements)
Shinny appearance (lustrous), durable, ductile, malleable, good conductors.
D-block called transition metals (G3-G12) sum of outer s & d electrons = group #
Less reactive metal, nonreactive – free in nature (Au, Pt, Pd)
Solid at room temperature except Hg

7. Regions Periodic table
Main group elements (representative elements):
Elements in s-block or p-block of the periodic table.
Groups 1, 2, 13-18
Alkali metals (G1):
Name from metals that react with water to form alkaline solutions.
Very reactive (1 valence electrons)
Stored in oil, not found free in nature, soft, good conductors of electricity.

8. Metal Regions on the P.T. Alkaline-earth metals (G2):
Highly reactive, not found free in nature
2 valence electrons, harder & higher melting point than G1
Lanthanides & actinides
f-block, rare-earth
Additional metal properties
Alloys: mixing 2 or more metals-> different properties than each metal. (brass Cu&Zn harder and corrosion resistant, sterling silver Ag&Cu used in jewelry, steel Fe&C

9. Nonmetals
Properties: brittle, dull, brightly colored, mostly gases at room temperature, poor conductors, not malleable or ductile.
Hydrogen
Most common element in the universe
Unique properties, separate classification.

10. Nonmetals Continue Halogens G17 Noble gases G18
Most reactive nonmetal, “salt maker”
7 valence electrons, gain 1 electron: meaning they like to react with group 1.
Noble gases G18
Inert gases, 8 valence electrons, non reactive.
Helium only needs 2 valence electrons to be considered to have a full shell.

11. Metalloids Elements that touch the stair case
B, Si, Ge, As, Sb, Te
Exception Al
Properties of both metals and nonmetals.
Solid at room temperature, shiny, somewhat malleable, conduct heat and electricity a little
Mixed groups 13-16

12. Periodic table trends
Trend: predicable change in a particular directions.
Make predictions about the chemical behavior of the elements
Based on electron configuration.
Trends:
Ionization
Atomic Radii
Electronegativity
Electron Affinity
Melting and Boiling Points

13. Ionization Energy Ionization energy:
Energy required to remove an electron from an atom or ion.
Overcome attractive force between protons and electrons.
Become positive charge (cation)
Atom + IE --> Cation (+) + electron
Trend: IE decrease down group, valence electrons further from nucleus and electron shielding -> decrease attractive force between nucleus and valance electrons
IE increases across a period, # of protons and electrons increase, higher nuclear charge and attractive forces -> decrease size

14. PT Trends continue Atomic radius: Volume occupied by electrons
Measured using bond radius. 1/2 distance from the center to center of two like atoms that are bonded together.
Trend: increases down group, increase energy levels and shielding decreases effective nuclear charged “felt” by valance electrons.
Decreases across period: across period increase # protons and electrons, shielding does not play a major role. Increase nuclear charge and attraction to electrons.

15. PT trends continue Electronegativity:
Measure of the ability of an atom in a chemical compound to attract electrons.
Know the strength of attraction -> predict chemical and physical properties.
Linus Pauling: scale of values, reflect how much an atom attract electrons. Increase value, increase attraction.
Trend: decrease down groups, electron shielding decreases attraction between valence electrons & effective nuclear charge, increase size and decrease attraction.
Increases across periods, increase # protons & electrons (electron shielding no change) -> increase effective nuclear charge -> electron attracted greater.

16. PT trend continue Ionic size:
Increase effective nuclear charge and attraction.
Cation decrease across period, anions decrease across period.
Electron affinity:
Gain electrons from neutral atom.
Increase from low left to upper right of the periodic table
Due to electron shielding and effective nuclear charge.

17. Melting & boiling pt trends
Across period:
2 peaks as d&p orbital fill
Increase # electrons -> stronger bonds between atoms -> more energy to melt or boil.
1st peak in d-block when orbital about 1/2 filled.
As decrease # of unpaired electrons-> decrease attraction.
2nd peak in p-block when orbital about 1/2 filled.

18. Problem
Arrange the following atoms by increasing atomic size, electronegativity, ionization energy and electron affinity.
Si, Ba, O, and Ge

19. Elements come from? 92 naturally occurring elements
Tc (technetium, Pm (promethium) & Np (neptunium) not found on earth but detected in spectrum of stars.
Most atoms in living things contain 6 elements
C,H,O,N,P and S

20. Mass  to energy Transmutations
 one element to another, nuclear reactions.
Synthetic elements: transuranium elements with more than 92 protons.
Particle accelerators (cyclotron) make super heavy elements.
Synthetic Elements:
Synthetic elements: transuranium elements with more than 92 protons
Particle accelerators make super heavy elements. Called Cyclotron.
Island of stability encountered around element 114.