Ch_02_Lecture_2[1]

Ch_02_Lecture_2[1] - Chapter 2 The Chemical Basis of...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chapter 2 The Chemical Basis of Life (Continued)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 + + + 2 2 2 Protons Neutrons Electrons Mass number = 4 + + 2e Electron cloud Nucleus 0 Figure 2.4A particles mass charge a. proton 1 +1 b. electron ~0 -1 c. neutron 1 0 Composition of an atom e.g., Helium electrons : in various orbital (shells) nucleus protons neutrons
Background image of page 2
3 Electrons in an atom Are arranged in shells, which may contain different numbers of electrons 0 Hydrogen (H) Atomic number = 1 Electron Carbon (C) Atomic number = 6 Nitrogen (N) Atomic number = 7 Oxygen (O) Atomic number = 8 Outermost electron shell (can hold 8 electrons) First electron shell (can hold 2 electrons) Figure 2.6 Electron arrangement 2.6 What determines the chemical properties of an atom?
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Atoms whose shells are not full Tend to interact with other atoms and gain, lose, or share electrons These interactions Form chemical bonds 0 1. covalent bonds: e.g., H 2 Two major chemical bonds to build compounds: 2. ionic bonds: e.g., NaCl 1. the resulting compound is electrically neutral Two rules are satisfied: 2. outer electron orbits are filled
Background image of page 4
5 2.7 Ionic bonds are attractions between ions of opposite charge When atoms gain or lose electrons ( outer shell) Charged atoms called ions are created 0 Transfer of electron Na Sodium atom Cl Chlorine atom Na + Sodium ion Cl Chloride ion Sodium chloride (NaCl) Na Cl Cl Na + Figure 2.7A When an atom loses an electron positive ion cation When an atom gains an electron negative ion anion
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 An electrical attraction between ions with opposite charges Results in an ionic bond 0
Background image of page 6
7 Sodium and chloride ions Bond to form sodium chloride, common table salt 0 Na + Cl Figure 2.7B
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8 2.8
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/07/2008 for the course BIO 100 taught by Professor Zhongma during the Spring '08 term at Truman State.

Page1 / 28

Ch_02_Lecture_2[1] - Chapter 2 The Chemical Basis of...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online