GOB9e_with_art_ch03 - Frederick A Bettelheim William H Brown Mary K Campbell Shawn O Farrell www.cengage.com\/chemistry\/bettelheim Chapter 3 CHEMICAL

GOB9e_with_art_ch03 - Frederick A Bettelheim William H...

This preview shows page 1 - 10 out of 48 pages.

Frederick A. Bettelheim William H. Brown Mary K. Campbell Shawn O. Farrell William H. Brown, Beloit College Chapter 3 CHEMICAL BONDS
Image of page 1
3-2 Lewis Model of Bonding In 1916, Gilbert N. Lewis pointed out that the lack of chemical reactivity of the noble gases indicates a high degree of stability of their electron configurations. He 1s 2 Ne Ar Kr Xe [He]2s 2p 6 [Ne]3s 2  3p 6 [Ar]4s 2  4p 6 [Kr]5s 2  5p 6 Noble gas Noble gas notation
Image of page 2
3-3 The Octet Rule Octet rule: Octet rule: The tendency of group 1A-7A elements to react in ways that achieve an electron configuration of eight valence electrons. An atom that loses one or more electrons becomes a positively charged ion called an cation. cation. An atom that gains one or more electrons becomes a negatively charged ion called a anion. anion.
Image of page 3
3-4 The Octet Rule Example: In losing one electron, a sodium atom forms a sodium ion, which has the same electron configuration as neon. Na (11 electrons): 1s 2 2s 2 2p 6 3s 1 Na + (10 electrons): 1s 2 2s 2 2p 6
Image of page 4
3-5 The Octet Rule Example: In gaining one electron, a chlorine atom forms a chloride ion, which has the same electron configuration as argon. Chlorine atom (17 electrons): 1s 2 2s 2 2p 6 3s 2 3p 5 Chloride ion (18 electrons): 1s 2 2s 2 2p 6 3s 2 3p 6
Image of page 5
3-6 The Octet Rule The octet rule gives us a good way to understand why Group 1A-7A elements form the ions they do; but it is not perfect: Ions of Period 1 and 2 elements with charges greater than +2 are unstable. For example, boron does not lose its three valence electrons to become B 3+ , nor does carbon lose its four valence electrons to become C 4+ . Ions of Period 1 and 2 elements with charges greater than -2 are also unstable. For example, carbon does not gain four valence electrons to become C 4- . The octet rule does not apply to Group 1B-7B (transition elements), most of which form ions with two or more different positive charges.
Image of page 6
3-7 Naming Cations Elements of Groups 1A, 2A, and 3A form only one type of cation. The name of the cation is the name of the metal followed by the word “ion”. Li + H + Hydrogen ion Lithium ion Sodium ion Potassium ion Ion K + Na + Mg 2+ Magnesium ion Calcium ion Strontium ion Barium ion Ca 2+ Sr 2+ Ba 2+ Al 3+ Aluminum ion Name Ion Name Ion Name Group 1A Group 2A Group 3A
Image of page 7
3-8 Naming Cations For cations derived from transition and inner transition elements, most of which form more than one type of cation: Use either Roman numerals to show charge or Use the suffix -ous -ous to show the lower positive charge and the suffix -ic -ic to show the higher positive charge.
Image of page 8
3-9 Naming Cations Table 3.2 Names of Cations from Four Metals That Form Two Different Positive Ions Fe 3+ Fe 2+ Hg + Hg 2+ Cu 2+ Cu + Copper(I) ion Copper(II) ion Iron(II) ion Iron(III) ion Mercury(I) ion Mercury(II) ion Cuprous ion Cupric ion Ferrous ion Ferric ion Mercurous ion Mercuric ion Cupr- from  cuprum , the Latin name for copper Hg from  hydrargyrum , the
Image of page 9
Image of page 10

You've reached the end of your free preview.

Want to read all 48 pages?

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes