Post on 06-May-2015
Chemistry for Biology
Biology ~ Edgar
Figure 2.1 The hierarchy of biological order from atom to organism
Figure 2.2b
TRUE FALSE
3 8 1. Table salt, water, and carbon are all compounds.
1 10 2. The smallest particle of an element is a molecule.
8 3 3. A bathtub full of lukewarm water may hold more heat than a teakettle full of boilling water.
10 1 4. *If the atmos in a molecule share electrons equaly, the molecule is said to be non-polar.
1 10 5. *Ice floats because water molecules in ice are more tightly packed then in liquid water.
9 2 6. *Atoms in a water molecule are held together by the sharing of electrons.
9 2 7. If solution-A has a pH of 2 and solution-B has a pH of 5 then solution-B is a stronger base then solution-A
10 1 8. An atom that has gained or lost electron is called an ion.
2 9 9. Hydrogen bonds are stronger then covalent bonds.
10 1 10. *Water is a good solvent in living organisms.
Table 2.1
LE 2-3
Sodium Chlorine Sodium Chloride
Figure 2.5 Two simplified models of a helium (He) atom
Figure 2.10 Electron configurations of the first 18 elements
Figure 2.12 Covalent bonding in four molecules
Figure 2.12x Methane
Figure 2.13 Polar covalent bonds in a water molecule
Figure 2.14 Electron transfer and ionic bonding
Figure 2.15 A sodium chloride crystal
Figure 2.16 A hydrogen bond
LE 2-4a
2
2
2
Protons
Neutrons
Electrons
Helium atom
Massnumber = 4
6
6
6
Protons
Neutrons
Electrons
Carbon atom
Massnumber = 12
Electroncloud
Nucleus
2e–
6e–
Table 2.4
LE 2-6a
ElectronOutermost electron shell (can hold 8 electrons)
First electron shell (can hold 2 electrons)
Hydrogen (H)Atomic number = 1
Carbon (C)Atomic number = 6
LE 2-6b
Nitrogen (N)Atomic number = 7
Oxygen (O)Atomic number = 8
LE 2-7
Transfer ofelectron
NaSodium atom
ClChlorine atom
Na
Sodium ionCl
Chloride ion
Sodium chloride (NaCl)
LE 2-7a-1
Transfer ofelectron
NaSodium atom
ClChlorine atom
LE 2-7a-2
Na
Sodium ionCl
Chloride ion
Sodium chloride (NaCl)
LE 2-7b
Na
Cl
LE 2-9
A water molecule
LE 2-10
Hydrogen bond
Figure 2.11
Figure 2.12
LE 2-13
Hydrogen bond
Ice
Hydrogen bonds are stable
Liquid water
Hydrogen bondsconstantly break and re-form
LE 2-14
Ion insolution
Saltcrystal
LE 2-15
Acidic solution
OH
H
HH
HOH
H H
H
OH
OH
OH
OH
OH
H
H
H
H
HH
I ncr
ea
sin
gl y
AC
IDI C
(Hi g
he
r c
on
c en
tra
t io
n o
f H
)Neutral solution
OH
OH
OH
OH
OH
OH
H
H
Basic solution
NEUTRALH
pH scale
Lemon juice, gastric juice
Grapefruit juice, soft drink
Tomato juice
Human urine
Pure water
Human blood
Seawater
Milk of magnesia
Household ammonia
Household bleach
Oven cleaner
Incr
ea
sin
gl y
BA
SIC
(Lo
we
r c
on
cen
tra t
i on
of
H )
Figure 2.16a
Figure 2.16b