Chapter 2: The Nature Of Molecules

Front 1

Matter

Back 1

All of the substances of the universe that have mass & occupy space

Front 2

Atoms are composed of:

Back 2

Protons

Neutrons

Electrons

Front 3

Protons

Back 3

Positively charged particles, always found in the nucleus

Front 4

Neutrons

Back 4

Neutral particles, always found in the nucleus

Front 5

Electrons

Back 5

Negatively charged particles that have almost no mass & are in constant motion

Front 6

Atomic Number

Back 6

the number of protons in a given atom

Front 7

Elements

Back 7

Atoms with the same atomic number

-pure substances that can't be broken down by ordinary chemical means

Front 8

Atomic Mass

Back 8

The sum of protons & neutrons

Front 9

Neutral Atoms

Back 9

Same number of protons and electrons

Front 10

Ions

Back 10

The number of electrons is not equal to the number of protons

-when atoms gain or lose electrons, they become negatively or positively charged

Front 11

Cations

Back 11

Have more protons than electrons and are positively charged

Front 12

Anions

Back 12

Have more electrons than protons and are negatively charged

Front 13

Isotopes

Back 13

Atoms of the same element that have different number of neutrons

Front 14

Oxidation

Back 14

An atom of molecule loses an electron

Front 15

Reduction

Back 15

An atom or molecule gains an electron

Front 16

Redox Reaction

Back 16

When the process of oxidation and reduction are coupled

-electrons carry energy from one mlc. to another

Front 17

Periodic Table

Back 17

Elements according to atomic number and properties

-Invented by Dmitri Mendeleev

Front 18

Valence Electrons

Back 18

electrons in the outermost energy level of an atom

-i.e.- Hydrogen has 1 valence electron

Front 19

Octet Rule

Back 19

Rule of eight

-atoms tend to establish completley fill outermost energy levels

Front 20

CHON

Back 20

Four elements found in large quantities:`

Carbon

Hydrogen

Oxygen

Nitrogen

Front 21

Molecules

Back 21

atoms held together in a stable association

Front 22

Compounds

Back 22

molecules containing more than one type of element

Front 23

Chemical Bonds

Back 23

A bond between atoms resulting from attraction from oppositely charged atoms

- the sharing of one or more pairs of electrons between atoms

Front 24

Covalent Bonds

Back 24

When two atoms share one or more paris of valence electrons

Build stable molecules

- i.e.- H2,O2, & N2

Front 25

Ionic Bonds

Back 25

formed by the attraction of oppositely charged ions

Front 26

Ionic Compounds

Back 26

Held together by Ionic bonds

Front 27

Ionization

Back 27

Ionic compounds tend to separate in water

Front 28

Electronegativity

Back 28

Atom's affinity for electrons

Front 29

Polar Covalent Bond

Back 29

molecule that has an uneven charge

Hint 29

Uneven

Front 30

Hydrogen Bonds

Back 30

Weak attractions between the partial negative regions & partial positive regions of water molecules.

Hint 30

Weak

Front 31

Cohesive

Back 31

The attraction of water molecules for each other

Hint 31

Attraction

Front 32

Hydrophobic Exclusion

Back 32

Nonpolar molecules tend to aggregate or organize in ways that minimize their contact with water.

Hint 32

Minimize

Front 33

Adhesive

Back 33

The ability of water to be attracted to itself & to other polar molecules or charged substances

Hint 33

Attracted

Front 34

Hydrogen Bonding

Back 34

Determines the high specific heat of water

Hint 34

High

Front 35

Soluble

Back 35

Ability of a substance to dissolve in solution

Hint 35

Dissolve

Front 36

Solvent

Back 36

The solute is dissolved

Front 37

Solute

Back 37

Substance that is dissolved

Front 38

Hydrophilic

Back 38

"Water Loving"

Front 39

Hydrophobic

Back 39

"water-fearing"

Front 40

Hydrophobic Exclusion

Back 40

Water forces the hydrophobic portions of molecules together.

Hint 40

Forces

Front 41

The pH Scale

Back 41

Measure hydrogen ion concentration

-pH= -log[H+]

Hint 41

Measure

Front 42

Acidic Solution

Back 42

pH less than 7

-H+ ion concentration is higher than OH- ion concentration

Front 43

Alkaline Basic Solution

Back 43

pH greater than 7;

-ion concentration is lower than OH- ion concentration

Front 44

Acid

Back 44

A chemical substance that releases H+ ions in water & increases the concentration of H+ ions

- Lower pH

Front 45

Base

Back 45

A chemical that accepts H+ ions & lowers the concentration of H+ ions

-Raises pH

Front 46

Buffer

Back 46

Acts as a reservoir for H+ ions by opposing resisting any changes in pH

Hint 46

Opposing

Front 47

Surface Tension

Back 47

The cohesion of water

Front 48

Specific Heat

Back 48

The amount of heat required to change one gram of substance one degree Celsius

Front 49

Heat of Vaporization

Back 49

The amount of heat required to change one gram of liquid to gass

Front 50

Evaporation Cooling

Back 50

The evaporation of water from a surface releases lots of heat energy, which cools the surface

Front 51

Hydration Shell

Back 51

This sphere of water molecules

Front 52

Mole

Back 52

Weight in grams of the sum of atomic masses