BIO 301M - Lecture 1 Chapters 2 4 carbon and the molecular...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 1: Chapters 2 & 4: carbon and the molecular diversity of life Concept 2.3: The formation and function of molecules depend on chemical bonding between atoms Covalent Bonds A covalent bond is the sharing of a pair of valence electrons by two atoms In a covalent bond, the shared electrons count as part of each atom’s valence shell A molecule consists of two or more atoms held together by covalent bonds A single covalent bond, or single bond , is the sharing of one pair of valence electrons A double covalent bond, or double bond , is the sharing of two pairs of valence electrons Figure 2.11 Formation of a covalent bond The notation used to represent atoms and bonding is called structural formula For example, H–H This can be abbreviated further with a molecular formula For example, H 2 Figure 2.12 Covalent bonding in four molecules Covalent bonds can form between atoms of the same element or atoms of different elements A compound is a combination of two or more different elements Bonding capacity is called the atom’s valence Electronegativity is an atom’s attraction for the electrons in a covalent bond The more electronegative an atom, the more strongly it pulls shared electrons toward itself In a nonpolar covalent bond , the atoms share the electron equally In a polar covalent bond , one atom is more electronegative, and the atoms do not share the electron equally Unequal sharing of electrons causes a partial positive or negative charge for each atom or molecule Figure 2.13 Polar covalent bonds in a water molecule Ionic Bonds Atoms sometimes strip electrons from their bonding partners
Background image of page 1

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

View Full DocumentRight Arrow Icon
An example is the transfer of an electron from sodium to chlorine After the transfer of an electron, both atoms have charges A charged atom (or molecule) is called an ion Figure 2.14 Electron transfer and ionic bonding A cation is a positively charged ion An anion is a negatively charged ion
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/07/2011 for the course BIO 301M taught by Professor Jasper during the Spring '08 term at University of Texas.

Page1 / 5

BIO 301M - Lecture 1 Chapters 2 4 carbon and the molecular...

This preview shows document pages 1 - 3. Sign up to view the full document.

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