i. history of the p.t. a.) dmitri mendeleev –russian chemist who 1st arranged elements in usable...
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I. History of the P.T.
• A.) Dmitri Mendeleev
– Russian Chemist who 1st arranged elements in usable manner (1869).
– Arranged elements in order of increasing atomic mass (“weight”).
History - Mendeleev (cont’d)
• Noticed chemical and physical properties appearing at periodic intervals.
• Paved the way for current P.T.
• “Father of the Periodic Table”
• Mendeleev link (pictures 1)
History – Henry Moseley
B.) Henry Moseley (1915)
• “Reorganized” the P.T.
• Arranged according to increasing atomic #.
• Current (present) P.T.
History – Periodic Law
• Periodic Law - Relationship b/t properties of elements and their atomic #.
• Physical and Chemical properties show a periodic pattern when arranged according to atomic #.
• P.T. is arranged according to this law.
II. Division of the P.T.
• Q.: How is the electron configuration affected???
– P.T. showing Ionization
A.) General Info.
• P.T. often includes phase at room temperature (temp.)
“STP” (Standard Temperature and Pressure) • Table A on Chemistry Ref. Tables.
• 3 Phases of matter . . .
– Solid (s), liquid (l), gas (g)
Phases @ STP
• Solid(s) – Vast majority of elements
• Liquid(l) – Hg (mercury – metal),
Br (bromine – nonmetal).
• Gas(g)– H, O, F, N, Cl, + Group 18
Group 18 = He, Ne, Ar, Kr, Xe, Rn
B.) Periods
• Horizontal () rows (1-7)
• Period # = # of E.L. (a.k.a. “principal energy levels” or “shells”)
– Eg.1: Elements in Period 3 have _____E.L.
Periods (cont’d)
Na Mg Al Si P S Cl Ar
• Q.1.: List how many E.L. each element has?
• Q.2.: List how many valence electrons each element has?
Periods (cont’d)
• # of valence electrons increases from left right
Periods (cont’d)
• Q.3.: How can we describe the location of solids and gases within a period?
• Solid (left side) Gas (right side)
• Q.4.: How can we describe the location of Metals and Nonmetals within a period?
• Metals (left side) Nonmetals (right side)
C.) Groups
• Vertical (up and down) columns (1-18).
1.) Elements in same group = same # valence electrons
– Except Helium.
Quick Review
• Q.1: What are valence electrons?
• Q.2: What is the maximum # of valence electrons allowed in an atom?
• Q.3: How many electrons do all elements want to have?
Groups (cont’d)
• Elements in the same group have more in common than elements in the same period.
• The closer the elements in the same group, the more similar their properties.
Important Group Names
Group(s) Group Name
1 Alkali Metals (Very Reactive)
2 Alkaline Earth Metals (Very Reactive)
3-11 Transition Metals (Transition Elements)
17 Halogens (Very Reactive)
18 Noble Gases (Not Reactive)*Stable
Properties of the Elements
• Q. What are the 3 types (not phases) of elements?
– Draw the Periodic Table and divide it according to these 3 types of elements.
METALS
• 75% of the Periodic Table
METALLOIDS (Semi-Metals)
• Stair line on P.T. (label it!)
• Share both Metal / Nonmetal properties
• Metalloids = B, Si, As, Ge, Sb, Te, At
– Al and Po are NOT metalloids.
• What are they???
NONMETALS
• Contain the only elements on the P.T. in the gas (g) phase.
Properties of the Elements
METALS NONMETALS
• Draw the Bohr models of Sodium and Chlorine (side-by-side)
– Q. How do the structures of these elements differ?
– Q. Describe what each will do to achieve the Octet Rule.
– P.T. showing Ionization
Properties of Metals
• Solid (except Hg)• Silver-colored (except Cu and Au)• Soft• Malleable – “hammered into shape”• Ductile – form into wire• Excellent conductors of heat and electricity• High melting point (M.P.)• Luster – shiny• Transitional Metals form colored compounds• Few valence electrons• Lose electrons to form “+” ions
• ** Which of the following metal ions forms a colored compound when bonded to a nonmetal?
1. K+1
2. Ba+2
3. Cu+2
4. Sr+2
Properties of Nonmetals
• All Phases (solid, liquid (Br), and gas)• Dull surface (no luster)• Hard solids• Brittle (not malleable or ductile)• Poor conductors of heat and electricity.• 4 or more valence electrons• Gain electrons to become “–” ions• Low Melting Point (in general)
Properties of Metalloids
• All solid (s) @ STP
• Contain properties of both Metals and Nonmetals.
• (First) Ionization Energy – amount of energy needed to remove the most loosely held electrons.
• Draw the Bohr models of Sodium and Fluorine (side-by-side)
– Q.1. Which element has a greater ionization energy?
– Q.2. What can we conclude about the ionization energy of metals compared to nonmetals?
The “Shielding” Effect
• The “Shielding” Effect refers to the weakening of attraction (“magnetic pull”) between the nucleus and the valence electrons, caused by the energy levels (shells) in between them.
** Shielding LOWERS the Ionization Energy! **
– Q.1. When does “Shielding” increase?
– Q.2. Which element would have more shielding, Chlorine or Bromine?
(First) Ionization Energy
• Draw Lithium and Sodium side-by-side
– Q.1. Which element has a greater ionization energy?
** Think in terms of MAGNETS! ** . . . (and the Shielding Effect)
• Q.4: Draw Na, Mg, and K side by side. Which of these 3 examples will take the least amount of energy (“ionization energy”) to lose 1 e ??? Why?
• Q. Which Metals do you think contain the MOST metal properties??? Explain.
• Q. Which Nonmetals do you think contain the MOST nonmetal properties??? Explain.
• Electronegativity – the attraction for electrons by an element
“Electronegativity is the attraction for an e”
• Draw the Bohr models of Lithium and Fluorine (side-by-side)
– Q.1. Which element has a greater electronegativity?
– Q.2. What can we conclude about the electronegativity of metals compared to nonmetals?
Electronegativity
• Draw Fluorine and Chlorine side-by-side
– Q.1. Which element has a greater electronegativity?
** Think in terms of MAGNETS! **
Electronegativity
• Draw Neon
– Q.1. How would you describe the electronegativity?
** Think in terms of MAGNETS! **
Atomic Radius
• Atomic Radius:• ½ the distance between two adjacent nuclei.
Trends in the P.T.• 1.) Reactive Groups:
– Metals: Group 1 (Alkali) and Group 2 (Alkaline Earth) are VERY REACTIVE!
• Group 1 are the MOST REACTIVE Metals.
• Reactivity of Group 1
– Nonmetals: Group 17 (Halogens) are VERY REACTIVE!
– Group 18 is STABLE (NOT Reactive)
Trends in the P.T.
• Atomic Radius– Within a Period
– Within a Group
• (Atomic Radii) (Atomic Radii.2) (Atomic Radii.3)
Trends in the P.T.
• Ionization energy
– Within a Period:
– Within a Group:
Trends in the P.T.
• Electronegativity
– Within a Period:
– Within a Group:
Graphing Trends
• Rule #1: Always set up graph as you do in all science/math classes.A.) Title: Independent (X) vs. Dependent (Y) Variable
B.) Set up X (independent) and Y (dependent) axes.
C.) Always have Equal INCREMENTS!!!
D.) Use as much of the graphing space as possible.E.) Always write a CONCLUSION!!!
• Rule #2: Make a Table!
– Refer to this table when making the graph.
Rule #3: Always circle your dots!
Graphing (Cont’d)
• 1.) Graph Group 1 (atomic #) vs. Electronegativity (Electron Affinity)
• 2.) Graph the trend of Ionization Energy in Period 2. (Period 2 vs. Ionization Energy)
• 3.) Graph the trend of Atomic Radius in Group 1. (Group 1 vs. Atomic Radius)
• Graphing Classwork/Homework.
Ionic Radius
• Ionic radius – The new radius of an element, after it becomes an ion.
– Eg. Draw Na and Cl. Show their radius as ions.
• What is the general rule for the ionic radius of Metals? Nonmetals?
Allotropes
• Allotrope: An element that exists as 2 or more forms in the same phase. Oxygen Ozone
FormO2 O3
Phase(g) (g)
The Element Song
The Element Song