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The Periodic Table
I. HistoryII. Arrangement of ElementsIII. Electron Configuration
TrendsIV. Periodic TrendsV. Reactivity
Mendeleev (1834-1907- Russian) (father of modern periodic table)Published system used today (1869)2. Elements arranged by increasing mass3. Left spaces for elements not yet discovered - predicted properties (scandium, gallium, germanium)
Dimitri Mendelev
E. Henry Mosley (1887-1915) English1.Arrange elements
by increasing atomic number – this led to the periodic law
2. Periodic Law - properties
of elements are periodic
functions of their atomic #
periodic repetition of
physical and chemical
properties
II. Arrangement of Elements
A. Periodic Table – arrangement of elements in order of increasing atomic number so that elements with similar properties are in the same column
period – horizontal row (7)
group(family)- vertical columns (1-18)
periodicity – reoccurrence of similar
properties of elements in groups
C. Special Groups on the Periodic Table
Periodic Table
D. Periodic Table Showing s,p,d,f Blocks
E. Metals – Metalloids - Nonmetals
1. Metals are on the left side – all are solids
except mercury (Hg)
a. elements near the left of a period are more metallic than those near the right
b. elements near the top of a group are more metallic than those near the bottom
2. Metalloids – group of elements between
metals and nonmetals(B,Si,Ge,As,Sb,Te)
3. Nonmetals are on the right side – all are
solids or gases except bromine(Br) liquid
Metals – Metalloids - Nonmetals
PROPERTY METAL NONMETAL
Luster high low
Deformability malleable brittle
and ductile
Conductivity good poor
Electron gain/lose lose gain
Ion formed cation (+) anion(-)
Ionization energy low high
Electronegativity low high
IV.Periodic Trends(Main Group Elements)
A. Atomic Radii 1. atomic radius is ½ the distance between nuclei of identical atoms joined in a molecule 2. decreases across periods (left-right) a. caused by increasing attraction between protons and electrons 3. increases from top to bottom a. caused by adding electrons to new shells
What is the atomic radius?
Atomic radii include the region in which electrons are found 90% of the time
Atomic Size
•Atomic Radius = half the distance between two nuclei of a diatomic molecule.
}Radius
Periodic Trends in Atomic Radii
Periodic Trends in Atomic Radii
Trends in Main Groups
Atomic Radii Period Trends
A. Periodic Trends in Atomic Radii
B. Ionization Energy
1. Energy required to remove an electron from an atom of an element (KJ/mol)2. Increases across periods (left to right) a. result of increased nuclear attraction3. Decreases down groups (families) a. electrons added to higher energy levels b. shielding effect of inner shell electrons c. repulsion of inner shell electrons4. Energy to remove second and third
electron is greater
B. Trend in Ionization Energy
B. Periodic Trends in Ionization Energy
Symbol First Second Third
HHeLiBeBCNO F Ne
1312 2731 520 900 800 1086 1402 1314 1681 2080
5247 7297 1757 2430 2352 2857 3391 3375 3963
11810 14840 3569 4619 4577 5301 6045 6276
C. Electronegativity1. Measures how strongly one atom
attracts the electrons of another atom when they form a compound
2. Increases across periods (left to right)
a. Fluorine has greatest value of 4
3. Decreases down groups
a. electrons far from the nucleus in
larger atoms have less attraction
b. Cesium and Francium with large radii
have the smallest electronegativity
Periodic Trends in Electronegativity
C. Periodic Trends in Electronegativity
C. Periodic Trends in Electronegativity
D. Ionic Radii1. Ion – atom that acquires a charge by
gaining or losing electrons
a. cation (+) ion anion (-) ion
2. Period trends
a. cation radii decrease across periods
b. anion radii increase across periods
3. Group trends
a. increase in cation and anion radii
down groups
Formation of an Anion (- ion)
D. Comparison of Atomic and Ionic Radii
D. Periodic Trends in Ionic Radii
E. Electron Affinity
1. Energy change that occurs when an electron is added to a neutral atom
2. If it is easy to add an electron to an
atom the energy value is negative
a. halogens have large negative values
3. If it is difficult to add an electron to an
atom the energy value is positive
a. atoms in groups 2 and 18 have high
positive values (due to filled subshells)
b. usually higher values in larger atoms
Electron Affinity for Chlorine
Periodic Trends in Electron Affinity
Periodic Trends in Electron Affinity
PERIODIC TRENDS
Periodic Trends in Melting Point
Periodic Trends in Density
V. Reactivity
A. Reactivity – measure of the tendency of an element to engage in chemical reactions by losing, gaining or sharing electrons
1. atoms of reactive elements are very
likely to gain, lose or share electrons
2. atoms of reactive elements are likely to form chemical bonds with other elements
B. Reactivity and the Periodic Table 1. alkali metals (group 1) most reactive metals 2. alkaline earth metals (group 2) second most reactive group of metals 3. halogens (group 17) most reactive nonmetals 4. noble gases (group 18) least reactiveC.Ionization Energy and Electronegativity 1. elements with very high and very low values are very reactive
Electron Arrangement and Reactivity
Electron Configuration
• S block [groups 1 and 2]
• P block [groups 13,14,15,16,17,18]
• D block [groups 3,4,5,6,7,8,9,10,11,12]
• F block (lanthanide and actinide series)
1s1 group 1
1s22s1
1s22s22p63s1
1s22s22p63s23p64s1
1s22s22p63s23p64s23d104p65s1
1s22s22p63s23p64s23d104p65s24d10
5p66s1
1s22s22p63s23p64s23d104p65s24d105p66s2
4f145d106p67s1
H1
Li3
Na11
K19
Rb37
Cs55
Fr87
• Alkali metals all end in s1
• Alkaline earth metals all end in s2
• Should include He but helium has the properties of the noble gases.
- its outer shell is filled with the
maximum number of electrons
allowed for the first shell (2)
s2s1 S- block
He2
Ne10
Ar18
Kr36
Xe54
Rn86
1s2
1s22s22p6
1s22s22p63s23p6
1s22s22p63s23p64s23d104p6
1s22s22p63s23p64s23d104p65s24d105p6
1s22s22p63s23p64s23d104p65s24d10
5p66s24f145d106p6
The P-block p1 p2 p3 p4 p5 p6
Transition Metals -d block
d1 d2 d3s1
d5 d5 d6 d7 d8s1
d10 d10
F - block• inner transition elements- hold a maximum
of 14 therefore there are 14 elements in both the actinides and lanthanides
f1 f5f2 f3 f4
f6 f7 f8 f9 f10 f11 f12 f14
f13
Group Ion Formed Electron Changes
• Group 1 X+
• Group 2 X2+
• Group 13 X3+
• Group 14 Xvaries
• Group 15 X3-
• Group 16 X2-
• Group 17 X-
• Group 18 X0
• Loses 1 electron
• Loses 2 electrons
• Loses 3 electrons
• Varies
• Gains 3 electrons
• Gains 2 electrons
• Gains 1 electron
• Does not gain or lose electrons
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