OLI AP Module 4-Module 5 atoms and bonding

module 4, module 5 chemistry, module 5 atoms and bonding

hierarchy of organization in body

organs

tissues

cells

cell organelles

macromolecules

molecules

atoms

ions

atoms that carry either a positive or negative charge from altered numbers of electrons

essential in physiological processes

atoms and ions

angstrom = 10^-10 m

molecules

nm = 10^-9 m

cells

micrometers = 10^-6 m

tissues

millimeters = 10^-3 m

organs

cm = 10^-2 m

key biologically relevant elements

hydrogen

carbon

nitrogen

oxygen

phosphorous

sulfur

what element is a major component of nearly all biological molecules

carbon

what percent of mass of a cell do biologically relevant elements represent

95%

elements are characterized by

atomic structure

valence electrons

electrons in outermost orbit involved in chemical bonding

atomic mass

protons + neutrons in atomic structure

molecular mass

sum of atomic mass of all atoms in a molecule

amu or Daltons

hydrogen atomic mass, valence electrons and covalent bonds

1 amu

1 ve

1 cb

carbon amu ve cb

12 amu

4 ve

4 cb

nitrogen amu ve cb

14 amu

5 ve

3 or 4 cb

oxygen amu ve cb

16 amu

6 ve

2 cb

phosphorus amu ve cb

31 amu 5 ve 3 cb

sulfur amu ve cb

32 amu

6 ve

2 cb

Cl amu ve cb

35 amu

7 ve

1 cb

electronegativity of an element

the degree to which an atom will attract electrons in a chemical bond

metals have low electronegativity

increases from left to right across periodic table

hydrogen electronegativity

2.1

carbon electronegativity

2.5

nitrogen electronegativity

3.0

oxygen electronegativity

3.5

phosphorous electronegativity

2.1

sulfur electronegativity

2.5

2 major chemical bonds

ionic

covalent

types of covalent bonds

polar covalent

nonpolar covalent

polar covalent

unique interaction between molecules

polar bonds interact with other polar bonds through intermolecular attraction hydrogen bonding

ions

form when an atom or atom group gains or loses one or more electrons

ionic bond

generally between atom of low electronegativity and atom of high electronegativity

metal and nonmetal

transfer of electrons not sharing

covalent bonds

molecules result from covalent bonding of two or more elements’ atoms

electrons are shared

no charge