1 Chapter 8 — Configurations — Part 1 1 CHAPTER 8 Periodic Properties of the Elements Chemistry (Custom UMD Edition) Nivaldo J. Tro 2 3
1 Chapter 8 — Configurations — Part 1
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CHAPTER 8 Periodic Properties of the Elements
Chemistry (Custom UMD Edition) #
Nivaldo J. Tro#
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• Coulomb’s Law describes the attractions and repulsions between charged particles#
• For like charges, the potential energy (E) is positive and decreases as the particles get farther apart as r increases#
• For opposite charges, the potential energy is negative and becomes more negative as the particles get closer together#
• The strength of the interaction increases as the size of the charges increases#
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• Each electron in a multielectron atom experiences both the attraction to the nucleus and repulsion by other electrons in the atom#
• These repulsions cause the electron to have a net reduced attraction to the nucleus – it is shielded from the nucleus#
• The total amount of attraction that an electron feels for the nucleus is called the effective nuclear charge of the electron#
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The periodic table is "blocked-out" in terms of the outermost electrons of the electronic configuration
of the elements. "
(n)S-Block
(n)P-Block (n-1)d-Block
(n-2)f-Block
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1#1#s#
value of n#value of l#
no. of#electrons#
spdf (or spectroscopic) notation#for H, atomic number = 1#
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Arrowsdepictelectronspin
ORBITAL BOX NOTATIONfor He, atomic number = 2
1s
21 s
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Ne # #Mn # #Zn # #Eu#
1s22s22p4 1s22s22p6 [Ar]184s23d1
[Kr]365s24d6 [Xe]546s24f145d106p5
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1s
2s
3s3p
2p
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• Movement of ions across cell membranes is the basis for the transmission of nerve signals
• Na+ and K+ ions are pumped across membranes in opposite directions through ion channels
• Na+ out and K+ in • The ion channels can differentiate Na+ from K+
by their difference in size • Ion size and other properties of atoms are
periodic properties – properties whose values can be predicted based on the element’s position on the Periodic Table
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decreases
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• Metals tend to lose electrons in reactions (low IE).
• Nonmetals tend to gain electrons (high IE).
• Metal oxides are basic in aqueous solutions.
• Nonmetal oxides are acidic in aqueous solutions.
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Isoelectronic: have the same number of electrons
Main group elements tend to become ions that are isoelectronic to their nearest noble gas element.
Na (1s22s2p63s1) Na+(1s22s2p6)
Larger main-group metals and transition metal tend to form pseudo inert-gas configurations:#
#[inner shell]ns2np6(n-1)d10#
Sn (..4s24p65s24d105p2) Sn4+((..4s24p64d10)
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• Ions, such as the transition metal ions, first lose electrons with the highest n value:
• Main group-s-block: remove all electrons with the highest n value.
• Main group-p-block: remove np electrons before ns electrons.
• Transition metals: remove ns electrons before (n-1)d electrons.
• Nonmetals: add electrons to the p orbitals of the highest n value.
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Fe3+ ions in Fe2O3 have 5 unpaired electrons and make the sample paramagnetic.#
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