Lecture3a

Lecture3a - Ionic bonding attraction between ions. Sodium...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
BIOLOGY 1001 Wednesday, January 23, 2008 Lecture 3 Building-Up Principle Electrons fill the shell closest to the nucleus, then begin to occupy the next shell. 1 st : 2 Electrons 2 nd : 8 Electrons 3 rd : 8 Electrons e.g., Atomic Number of Carbon (C) = 6 6 Electrons 2 in 1 st Shell 4 in 2 nd Shell Electron Shells p. 24 Isotopes Isotopes vary in number of neutrons. p. 23 Ions Atoms are most stable with the full outer shell. Extra Electrons: - Charge Fewer Electrons: + Charge Figure 2-3 p. 25 What determines whether Atoms will interact? Answer: The Number and arrangement of their electrons. p. 24 Bond is union between electrons in an outer shell of atoms. Atoms bond to form molecules. Molecules may obtain atoms only one element - O 2 Compounds contain more than one element – H 2 O
Background image of page 1

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

View Full DocumentRight Arrow Icon
Important Bonds in Biological Molecules Ionic Bonds, Covalent Bonds, and Hydrogen Bonds
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Ionic bonding attraction between ions. Sodium can lose 1 electron chlorine can gain 1 electron. Sodium becomes a + ion. Chlorine becomes a - ion. Table 2-2, Figure 2-3, p. 25-26 Covalent Bonding: Atoms share electrons to fill outermost shell. Single Covalent Bond 1 Pair Electrons Double Covalent Bond 2 Pair Electrons Triple Covalent Bond 3 Pair Electrons Figure 2-4, p. 26 Non-polar Covalent Bonds Atoms share electrons equally. Hydrogen Gas (H-H), Methane (CH 3 ) Figure 2-4, p.26 Polar Covalent Bonds Electrons spend more time around one atom and less around another. Figure 2-4, p. 26 Hydrogen Bonds Polar molecules carry slight charges Electrons favor one atom over another. Hydrogen bond forms between + end of one molecule and - end of another. Figure 2-5, p. 28...
View Full Document

This note was uploaded on 06/09/2010 for the course BIOL 1001 taught by Professor Minor during the Spring '08 term at LSU.

Page1 / 2

Lecture3a - Ionic bonding attraction between ions. Sodium...

This preview shows document pages 1 - 2. Sign up to view the full document.

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