Study Sheet for Chapter 2Honors Biology

EXTENDED RESPONSE TIPS:

• EXAMPLE: • Surface tension caused by the pulling in of H-

bonds of the water molecules. This creates a “film” on the surface of the water.

• This allows small insects to walk on the surface of water.

#1Atom = 1 unit – smallest unit of an element

• Symbol = abbreviation of an element

• Element = 1 kind of substance that cannot be broken down by chemical means – listed on Periodic table

Molecule = 2 or more atoms chemically bonded (can be same or different)

• Formula = abbreviation of a compound

• Compound = 2 or more different elements bonded together chemically

#2

• 59 • Co• 27• Mass number = 59• Atomic number = 27• Number of protons = 27• Number of electrons = 27• Number of neutrons = 32

#3

• Trace elements

• Appear in very small amounts• Milligrams (mg)

#4

• Radioactive isotope

• Breaks down spontaneously• (gives off energy and particles, can be

detected on a PET scan)• Break down to their more stable form• EX: C-14 to C-12

#5

• Why do atoms join to form compounds?

• TO FILL THEIR OUTER ELECTRON SHELL

#6

• IONS and ISOTOPES

• IONS = differ in the number of electrons (charged atoms)

• ISOTOPES = differ in the number of neutrons (different mass numbers)

#7

• Electrons in covalent and ionic bonds

• COVALENT = electrons are shared

• IONIC = electrons are transferred (lost/gained)

#8

• Solute and solvent and solution

Water = solvent – does the dissolving (larger amount)

Sugar = solute –being dissolved

Both = solution

#9

• H-bonding

• When water reaches 4oC and below H-bonds form an open lattice (less dense)

• For surface tension, H-bonds pull the water molecules inward to form a “film”

#10

• IN ORDER (strongest to weakest):

• COVALENTIONICH-bonding

Van der Waals

#11

• Buffers

• Minimize the change in pH by adding extra H+ and OH-

#12

• ACIDS put H+ ions into solution• (H+ donors)

• BASES put OH- ions into solution• (OH- donors)

#13

• Water has high heat of vaporization (slow to heat and also slow to cool)

• So the coastal area temperatures would change less rapidly than inland areas

#14

ACIDS

• Strong 1-3• Weak 4-6

• pH 3 = [H+] 10-3

• pH 4 is 100 X’s the H+ ions than pH 6

BASES

• Strong 11-14• Weak 8-10

• pH 11 = 10-11

#15

• Electrons fill• 2• 8• 8

#16

• ACID PRECIPITATION• pH lower than 5.2

#17• COVALENT BONDS

How can they be written?

• Single bond double bond triple bond

• C-C C=C C=C

• C:C C::C C:::C

• 2 e- 4 e- 6 e-

#18

• H+ ions surround Cl-

• OH- ions surround Na+

#19

• REACTANTS PRODUCTS• Left of arrow right of arrow

#20

+1 +2 share -3 -2 -1 0

e- in outer shells

Ion formed

e- in outer shell

Full outer e-shells

H

8

#20

• Elements that are located in the same column behave more alike chemically

#21

• Polar Covalent = unequal sharing of e-

• Nonpolar Covalent = equal sharing of e-

#22

• Bohr Model

#23

H-H O-H NaCl

#24

• UNIQUE PROPERTIES OF WATER

• 1. H-bonding• 2. Polarity

#25

• CHON

• Trace element in mg

#25

• Fe• Used by RBC to carry oxygen in hemoglobin

• I• used to prevent blindness and have proper

use of thyroid

• F• used to prevent tooth decay•

#26

• Elements have different numbers of protons

• Elements have different numbers of electrons (form different ions and different bonds)

#26

• Same column have same outer shell (valence) electrons

+1 +2 share -3 -2 -1 0

e- in outer shells

Ion formed

e- in outer shell

Full outer e-shells

H

8

#27

• ISOTOPES OF AN ELEMENT• Same number of protons (same atomic

number)• Different number of neutrons (different mass

number)

#28

• Valence electrons (fill inner shell first)• 2• 8• 8

Fill in the chart of e-

Element Number of e-

First shell Second Third

Shell Shell

carbon 6 2 4

lithium 3 2 1

Sodium 11 2 8 1

Oxygen 8 2 6

#29

• If atomic number 8• Can form two more bonds

#30

• BOTH INTERMOLECULAR

• Van der Waals = are momentary very weak forces of attraction between nonpolar molecules resulting from uneven electron distributions(EX: gecko hairs on feet and glass)

• H-bonding = forces between H and F, O, or N

#31

• Cations = (+) ions

• Anions = (-) ions

#32

You need to break the H-bonds to vaporize (form a gas)- takes extra time

You need to form H-bonds to form ice – takes extra time

#33• pH [H+] [OH-] [H+] X [OH-]

• 0 1 X 10-0 1 X 10-14 1 X 10-14

• 1 1 X 10-1 1 X 10-13 1 X 10-14

• 2 1 X 10-2 1 X 10-12 1 X 10-14

• 3 1 X 10-3 1 X 10-11 1 X 10-14

• 4 1 X 10-4 1 X 10-10 1 X 10-14

• 5 1 X 10-5 1 X 10-9 1 X 10-14

• 6 1 X 10-6 1 X 10-8 1 X 10-14 acid

• 7 1 X 10-7 1 X 10-7 1 X 10-14 neutral

• 8 1 X 10-8 1 X 10-6 1 X 10-14 base

• 9 1 X 10-9 1 X 10-5 1 X 10-14

• 10 1 X 10-10 1 X 10-4 1 X 10-14

• 11 1 X 10-11 1 X 10-3 1 X 10-14

• 12 1 X 10-12 1 X 10-2 1 X 10-14

• 13 1 X 10-13 1 X 10-1 1 X 10-14

• 14 1 X 10-14 1 X 10-0 1 X 10-14

Determine the pH• [H+] [OH-] = 10-14

•If [H+] = 10-4 = pH 4•[OH-] = 10-10

#34

• Mg-2 Cl-

• K+ I-

• Ca+2 P-3

#35

• REVIEW YOUR ELEMENTS AND SYMBOLS:

• Ca = calcium• C = carbon• Co = cobalt

#36 EXAMPLE

• Why water makes a nice drop on wax paper:• Surface tension on the water.• Strong cohesion of the water molecules• Weak adhesion to the wax paper.

• Review blue sheet, water properties quiz and lab.