Chemistry 1 Unit 2 Full Notes, Lecture notes of Chemistry

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UNIT 2

Periodic Table

 Why is the Periodic table So important in science?

Learning Targets

 (1) I can identify trends in ionization energy, electronegativity, and the relative size of atoms and ions

 (2) I can identify the different parts of the periodic table: metals, non-metals, metalloids, transition metals, inner transition metals, representative elements, alkali metals, alkaline earth metals, halogens, noble gases, lanthanide and actinide series.

 (3) I can predict relative sizes of neutral atoms in comparison to their ions

Background

 https://www.youtube.com/watch?v=0RRVV4Di omg

 https://www.youtube.com/watch?v=Zg6KeXsD VwY

 Key ideas

 The Periodic table is a very important tool in science

 tells us….

 (1) charges of atoms when they become ions

 (2) number of valence electrons

 (3) structure of atoms

 (4) reactivity

 (5) properties.

Background

 Needed to organize the known elements

 Key Person

 Dimitri Mendeleev, 1869 (63 elements)

 Russian scientist

 Organize known elements according to their increasing atomic mass & chemical/physical properties

 Problem? Ar vs K Te vs I Co vs Ni

 Modern Periodic Table

 Henry Moseley: a student of Ernest Rutherford

General Set-Up

 Vertical part called Columns, Groups or

Families

 Numbers above the columns are called…

 Column numbers

 Horizontal part are called rows or periods

 The numbers next to the periods are called…

 Period numbers

 Names of Families

 1A, 2A, 7A, 8A

General Set-Up

 Names of Families  1A alkali metals  Soft (cut with a knife)  Reacts violently in water  Top to bottom more violent  Creates a basic solution: pH above 7 & has a slippery or slimy  https://www.youtube.com/watch?v=NTFBXJ3Zd_4 Na video  https://www.youtube.com/watch?v=RNyTba-AKjA alkali metals  https://www.youtube.com/watch?v=CEC64Bqeajs Na toilet  Cesium: https://www.youtube.com/watch?v=fPk1hKLRyeE

General Set-Up

 7A Halogens

 Halide means salt….NaCl, KI, LiCl

 A salt is a biproduct of an acid /base

reaction

 NaOH(aq) base + HCl(aq) acid  H 2 O(l) +

NaCl(s) salt.

 8A Noble gases

 Non active or Inert.

General Set-Up

Metals: characteristics (on test)

 Conduct electricity

 Conduct heat

 Has a luster or shine

 Solid at room temperature (except…)

 Malleable (capable of being shaped) , and

ductile (can be drawn thin into wire)

General Set-Up

 Some Gases = H, N, O, F, Cl and noble gases

 Few Liquids = Br, Hg

 Transition metals & inner transition metals:

location?

General Set-Up

Transition metals

 Transition metals

 (c) They have compounds that are colored:

Fe 2 O 3 (rust) iron III oxide is reddish

 Manganese III Chloride, MnCl 2 is a purple

color.

 (d) some are magnetic.

• Monatomic atoms vs Di atomic molecules
• Atom = single substance Molecule ~ compound
• Sodium atom exists by itself as Na
• Oxygen gas molecule exists as two O-atoms together, O 2.
• Call this a diatomic molecule.
• There are 7 diatomic molecules on the periodic table
• Start with #7 and make a 7, & include H
• Or, Br, I, N, Cl, H, O, F (BrINClHOF)

 An early observation of the Periodic

Table gave rise to the Law of

Octaves.

 Every 8th^ element repeats similar

chemical/physical properties.

 This idea was sufficient for a period of

time until more elements were

discovered.

Core electrons vs Valence electrons

 How many electrons does lithium have?, Boron? Oxygen? Potassium? Aluminum? Sulfur?

 The most important electrons of an atom is it’s outer most electrons, called VALENCE electrons.

 Focus on the valence electrons b/c…

 1) they are responsible for the element’s properties (bonding)

 2) the first substances that interact during a reaction.