1. Chapter 6 The Periodic Table 6.3 Periodic Trends
6.1 Organizing the Elements
6.2 Classifying the Elements
6.3 Periodic Trends
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2. Trends in Ionization Energy
Atomic Radius – one-half the distance between the nuclei of two atoms of the same element when the atoms are joined.
Ionization Energy – energy required to remove one electron from an atom.
Electronegativity – ability of an atom of an element to attract electrons when the atom is in a compound.
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3. Trends in Atomic Size
Atomic Radius: one-half the distance between the nuclei of two atoms of the same element when the atoms are joined.
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4. Trends in Atomic Size
In general, atomic size increases from top to bottom within a group, and decreases from left to right across a period.
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5. Trends in atomic size. Trends in Atomic Size
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6. Which atom in each pair has the larger atomic radius? Li or K Ca or Ni
CHEMISTRY & YOU
Which atom in each pair has the larger atomic radius?
Li or K
Ca or Ni
Ga or B
O or C
Cl or Br
f) Be or Ba
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7. Which atom in each pair has the larger atomic radius? Li or K Ca or Ni
CHEMISTRY & YOU
Which atom in each pair has the larger atomic radius?
Li or K
Ca or Ni
Ga or B
O or C
Cl or Br
f) Be or Ba
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8. HW #38 - Which element in each pair has the larger atomic radius?
CHEMISTRY & YOU
HW #38 - Which element in each pair has the larger atomic radius?
Na or Li
Sr or Mg
C or Ge
Se or O
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9. HW #38 - Which element in each pair has the larger atomic radius?
CHEMISTRY & YOU
HW #38 - Which element in each pair has the larger atomic radius?
Na or Li
Sr or Mg
C or Ge
Se or O
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10. Ions An atom or group of atoms that has a positive or negative charge.
Atoms become ions when electrons are lost or gained.
Atoms can become cations or anions
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11. Cation – ion with a positive charge
Ions
Cation – ion with a positive charge
Metals tend to form cations.
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12. Anion – ion with a negative charge
Ions
Anion – ion with a negative charge
Nonmetals tend to form anions.
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13. Cations are always smaller than the atoms from which they form.
Trends in Ionic Size
Trends in Ionic Size
Cations are always smaller than the atoms from which they form.
Anions are always larger than the atoms from which they form.
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14. Group Trends in Ionic Size
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15. The figure below summarizes the group and period trends in ionic size.
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16. HW #44 – Which particle has the larger radius in each atom/ion pair?
CHEMISTRY & YOU
HW #44 – Which particle has the larger radius in each atom/ion pair?
Na, Na+
S, S2-
I, I-
Al, Al3+
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17. HW #44 – Which particle has the larger radius in each atom/ion pair?
CHEMISTRY & YOU
HW #44 – Which particle has the larger radius in each atom/ion pair?
Na, Na+
S, S2-
I, I-
Al, Al3+
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18. Trends in Ionization Energy
Ionization Energy – energy required to remove one electron from an atom.
The energy to remove the first electron is called the first ionization energy.
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19. Ionization Energies of Some Common Elements
Interpret Data
Ionization Energies of Some Common Elements
Symbol
First
Second
Third H
1312
He (noble gas)
2372
5247 Li
520
7297
11,810 Be
899
1757
14,840 C
1086
2352
4619 O
1314
3391
5301 F
1681
3375
6045
Ne (noble gas)
2080
3963
6276 Na
496
4565
6912 Mg
738
1450
7732 S
999
2260
3380
Ar (noble gas
1520
2665
3947 K
419
3096
4600 Ca
590
1146
4941
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20. 1. Which has the smallest ionization energy;
Trends in Atomic Size
Practice Problems
1. Which has the smallest ionization energy;
Sodium, Calcium, Potassium, Magnesium
2. List in order of increasing ionization energy (smallest to largest)
Beryllium, Cesium, Oxygen,
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21. CHEMISTRY & YOU
HW #40 - Which element in each pair has a greater first ionization energy?
Li or B
Mg or Sr
Cs or Al
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22. CHEMISTRY & YOU
HW #40 - Which element in each pair has a greater first ionization energy?
Li or B
Mg or Sr
Cs or Al
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23. CHEMISTRY & YOU
HW #41 – Arrange the following groups of elements in order of increasing ionization energy.
Be, Mg, Sr
Bi, Cs, Ba
Na, Al, S
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24. CHEMISTRY & YOU
HW #41 – Arrange the following groups of elements in order of increasing ionization energy.
Be, Mg, Sr → Sr, Mg, Be
Bi, Cs, Ba → Cs, Ba, Bi
Na, Al, S → Na, Al, S
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25. Electronegativity Values for Selected Elements
Interpret Data
Electronegativity – ability of an atom of an element to attract electrons when the atom is in a compound.
Electronegativity Values for Selected Elements H
2.1 Li
1.0 Be
1.5 B
2.0 C
2.5 N
3.0 O
3.5 F
4.0 Na
0.9 Mg
1.2 Al Si
1.8 P S Cl K
0.8 Ca Ga
1.6 Ge As Se
2.4 Br
2.8 Rb Sr In
1.7 Sn Sb
1.9 Te I Cs
0.7 Ba Tl Pb Bi
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26. Trends in Electronegativity
In general, electronegativity values decrease from top to bottom within a group. For representative elements, the values tend to increase from left to right across a period.
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27. CHEMISTRY & YOU
HW #45 - Which element in each pair has a higher electronegativity value?
Cl or F
C or N
Mg or Ne
As or Ca
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28. CHEMISTRY & YOU
HW #45 - Which element in each pair has a higher electronegativity value?
Cl or F
C or N
Mg or Ne
As or Ca
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29. CHEMISTRY & YOU
HW #47 – When the elements in each pair are chemically combined, which has a greater attraction for electrons?
Ca or O
O or F
H or O
K or S
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30. CHEMISTRY & YOU
HW #47 – When the elements in each pair are chemically combined, which has a greater attraction for electrons?
Ca or O
O or F
H or O
K or S
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31. Trends in Electronegativity
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32. Mendeleev’s Periodic Table
How did Mendeleev organize his periodic table?
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33. Trends in Atomic Size
Do Now:
Without looking at your periodic table, classify each of the following elements K Ca Al F Ar U
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34. Reading the Periodic Table
Do Now:
Which element has chemical properties similar to Oxygen?
Lithium, Neon, Phosphorus, or Sulfur
Classify each as metal, metalloid, or nonmetal.
Aluminum
Silicon
Phosphorus
Cadmium
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