Ch. 2 PT.notebook
October 16, 2014
Chapter #2 The Periodic Table
Mendeleeve – (1834 – 1907), arranged the elements within a group in order of their atomic mass. He noted repeating patterns in their physical and chemical properties
Element Song in Japanese
Periodic Table of Elements ­ Chemistry: A Volatile History ­ BBC Four Element Song
Nov 17 ­ 10:47 AM
Henry Moseley – (1887­1915), Arranged the elements in a table by order of Atomic Numbers. Alternative Periodic Tables
Nov 17 ­ 10:47 AM
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Ch. 2 PT.notebook
October 16, 2014
Periods – the horizontal rows of the periodic table
Groups or Families – the vertical columns of the periodic table
Periodic Law – when elements are arranged in order of increasing atomic number, a periodic pattern occurs in their physical and chemical properties
Nov 17 ­ 10:50 AM
Metals
Most elements on the P.T. are metals. Physical Properties of Metals:
• Luster (shininess) • Good conductors of heat and electricity • High density (heavy for their size) • High melting point • Ductile (most metals can be drawn out into thin wires) • Malleable (most metals can be hammered into thin sheets) Chemical Properties of Metals:
• Easily lose electrons • Corrode easily. Corrosion is a gradual wearing away. (Example: silver tarnishing and iron rusting) Nov 17 ­ 10:51 AM
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Ch. 2 PT.notebook
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Nonmetals
Nonmetals are found to the right of the stair step line. Their characteristics are opposite those of metals.
Physical Properties of Nonmetals:
• No luster (dull appearance) • Poor conductor of heat and electricity • Brittle (breaks easily) • Not ductile • Not malleable • Low density • Low melting point
• Many are gases at room temperature.
Chemical Properties of Nonmetals:
• Tend to gain electrons • Since metals tend to lose electrons and nonmetals tend to gain electrons, metals and nonmetals like to form compounds with each other. Nov 17 ­ 10:57 AM
Metalloids
Elements on both sides of the steps have properties of both metals and nonmetals. These elements are called metalloids or semimetals.
Physical Properties of Metalloids:
• Solids • Can be shiny or dull • Ductile • Malleable • Conduct heat and electricity better than nonmetals but not as well as metals Nov 17 ­ 10:57 AM
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Ch. 2 PT.notebook
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The transition metals are the metallic elements that serve as a bridge, or transition, between the two sides of the table. The lanthanides and the actinides at the bottom of the table are sometimes known as the inner transition metals Nov 17 ­ 10:57 AM
Main Blocks of the P.T
• Groups 1 and 2 of the P.T are referred to as the s block because these elements have outer electrons in an s orbital. • Groups 13­18 are the p block because these elements have outer electrons in the p orbitals. Also called the representative elements.
• Groups 3­12 are referred to as the d block and the inner transition elements are f block. Jan 5­10:29 AM
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Ch. 2 PT.notebook
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Valence Electron(s) – electron(s) in the outermost energy level of an atom. In a period from L to R on the P.T the number of valence electrons increases by one.
In a group, the group number is related to the umber of valence electrons.
Nov 17 ­ 10:53 AM
The Alkali metals ­ group 1 of the P.T, are very reactive metals. They do not occur freely in nature. They have only 1 valence electron in their last energy level. The Alkaline Earth metals ­ group 2 of the P.T. These metals have 2 valance electrons in their last energy level.
THE NOBLE GASES
The gases in column 18 or 8.
All of the Noble gases are inert. They have 8 electrons on their last energy level, (except for He with 2 electrons). Noble gases rarely combine with other elements. Nov 17 ­ 10:58 AM
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Ch. 2 PT.notebook
October 16, 2014
HALOGENS Located in column 7 or 17 of the P.T. The halogens have 7 e­ in their last energy level.
They are all just one electron short of having a full shell. (8 valance electrons)
They often bond with metals and elements from Group 1 of the P.T
When a halogen combines with another element, the resulting compound is called a halide. Nov 17 ­ 2:14 PM
Boron Family ­ Group 3 or 13. They have 3 e­ s in the last energy level. Boron is a metalloid. The other members of this family are metals. The Carbon family ­ Group 4 or 14. All members of the carbon family have 4 e­ s in their last energy level. The Nitrogen family ­ Group 5 or 15. All members of the nitrogen family have 5 e­ s in their last energy level. The Oxygen family ­ Group 6 or 16. All members of the nitrogen family have 6 e­ s in their last energy level. Their properties go from nonmetallic in oxygen and sulfur to metalloid in tellurium to metallic in polonium. Nov 17 ­ 2:14 PM
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Ch. 2 PT.notebook
October 16, 2014
Periodic Trends: Reactivity Alkalie Metals
Li, Na, K
Halogens
Alkaline Metals
Reaction of Na & Cl2
Reactivity of Halogens
Nov 22 ­ 11:49 PM
Atomic Radius ­ is half the distance between the nuclei of two atoms in a homonuclear diatomic molecule.
Atomic Radius Trends
• Atomic size generally increase as we move down the group.
• Atomic size generally decrease as we move from left to right across the period.
Nov 22 ­ 11:49 PM
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Ch. 2 PT.notebook
October 16, 2014
Jan 13­9:27 PM
Atomic Radius Trend Graph
Atomic Radius Trends Practice:
1. Which of the following has a greater atomic radius?
a. Na, Li
b. Sr, Sb
c. C, Te
d. Se, Po
2. Arrange the elements in order of increasing atomic radius
a. S, Cl, Al, Na
b. Mg, Sr, F, B
c. Bi, Cs, Ba, I
d. P, F, Ra, Cs
Nov 23 ­ 12:04 AM
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Ch. 2 PT.notebook
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Ionic Radius ­ Ions will have a different size than the atoms they come from. Positive ions ­ are smaller than the atoms they come from.
Nov 23 ­ 12:06 AM
Negative ions ­ are bigger than the atoms they come from. Ionic Radius Trends Practice 1. Which of the following has a greater ionic radius?
a. Na+, Li+
b. Sr2+, Al3+
c. O2­, S2­
d. K+, P3­
2. Arrange the elements in order of decreasing ionic radius
a. S2­, Cl­, Al3+, Na+
b. Mg2+, Sr2+, F­, B3+
Nov 23 ­ 12:06 AM
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Ch. 2 PT.notebook
October 16, 2014
The Octet Rule and Common Ions
Draw the Bohr ring models for:
Li and F
Jul 14­10:32 AM
Ionization Energy ­ the energy required to remove an electron from a gaseous atom. I. E. Trends • The first ionization energy generally decreases as we move down the group.
• The first ionization energy generally increases as we move from left to right across the period. Nov 29 ­ 7:37 AM
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Ch. 2 PT.notebook
October 16, 2014
I. E. Trends Practice Arrange the elements in order of increasing ionization energy
b. Mg, Sr, F, B
a. S, Cl, Al, Na
d. P, F, Ra, Cs
c. Bi, Cs, Ba, I
Successive IE
Nov 29 ­ 7:39 AM
Second Ionization Energy
Second ionization energy is defined by the equation:
It is the energy needed to remove a second electron from gaseous 1+ ion to give gaseous 2+ ion.
You can then have as many successive ionization energies as there are electrons in the original atom.
The first four ionization energies of aluminum, for example, are given by
1st I.E. = 577 kJ mol­1
2nd I.E. = 1820 kJ mol­1
3rd I.E. = 2740 kJ mol­1
4th I.E. = 11600 kJ mol­1
Dec 6­9:55 PM
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Ch. 2 PT.notebook
October 16, 2014
Electron Affinity Trend the energy given off when a neutral atom in the gas phase gains an extra electron to form a negatively charged ion. H(g) + e­ → H­(g); ΔH = ­73 kJ/mol. Electron Affinity Trends
• Electron Affinity energy generally decreases as we move down the group.
• Electron Affinity energy generally increases as we move from left to right across the period. Jul 25­1:47 PM
Electron Affinity Trends Practice Arrange the elements in order of increasing electron affinity
a. O, F, N, Mg
b. K, Si, Cl, Al
c. Rb, Sn, Sr, I
d. P, Br, Ca, Li
Jul 25­1:56 PM
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Ch. 2 PT.notebook
October 16, 2014
Electronegativity – the ability of an atom to attract electrons to itself when it is chemically combined with another element. Values are 0­4
Electronegativity Trends:
Generally decreases as you go down the family.
Generally increases as you move from left to right across a period
Dec 2­10:41 AM
Electronegativity Trends Practice Arrange the elements in order of increasing electron affinity
a. O, F, N, Mg
b. K, Si, Cl, Al
c. Rb, Sn, Sr, I
d. P, Br, Ca, Li
Dec 2­10:41 AM
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Ch. 2 PT.notebook
October 16, 2014
Jul 11­2:18 PM
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