Concepts Of Science Chapter 8

Front 1

Dalton

Back 1

(1766-1844)Hypothesized that for every chemical element there is a corresponding species of objects called atoms. this atom cannot be broken down any more.

Front 2

Molecule

Back 2

Any cluster of atoms that can be isolated

Front 3

electrolysis

Back 3

"splitting by electricity" allowed for rapid discovery of many elements.

Front 4

earth's composition

Back 4

99% made of six elements: oxygen, silicon, magnesium, iron, aluminum, and calcium

Front 5

Rutherford's model of the atom

Back 5

a dense positively charged nucleus surrounded by oribiting cloud of negatively charged electrons

Front 6

other discoveries

Back 6

for each proton in nucleus there is an electron in orb it thus electrical charges of an atom cancel out and the intact atom is neutral;
if an atom should gain or lose an electron this affects its overall charge; charged atoms are called ions.

Front 7

ground state of atoms

Back 7

all electrons in lower energy level.

Front 8

excited state of atoms

Back 8

some or all electrons are in the highest energy levels

Front 9

photon

Back 9

in bohr model when an electron drops an energy level it emits energy(visible light)

Front 10

quantam leap

Back 10

an electron must disappear and reappear on another level without transversing the distance and with no time distance

Front 11

stars

Back 11

made mainly of two elements: hydrogen and helium

Front 12

living organisms

Back 12

90% hydrogen carbon nitrogen oxygen phosphorus sulfur

Front 13

Thompson

Back 13

identified a subatomic particle called the electron, negatively charged

Front 14

Rutherford

Back 14

experimented with gold foil, proved existence of the nucleus

Front 15

electromagnetic radiation

Back 15

electrons don't fall into the nucleus

Front 16

Bohr

Back 16

said that electrons exist in various levels or shells located about the nucleus each shell corresponds to an energy level of the electron

Front 17

spectrum

Back 17

total collection of photons omitted by a given atom therefore each has a unique spectrum.

Front 18

emmission and absorption

Back 18

each element will emit and absorb light of the same wavelenght transparent or feflecting materials absorb specific wavelengths of light according to their atomic structure.

Front 19

spectroscopy

Back 19

study of elemental composition of materials by looking at absorption lines

Front 20

helium

Back 20

the elusive element, first found in suns light but not found on earth until 30 years later.

Front 21

laser

Back 21

light amplification by stimulated emission of radiation

Front 22

periodic table of elements

Back 22

elements arranged by their chemical properties.

Front 23

atomic number

Back 23

defines the sequence of elements in the table; number of protons in nucleus

Front 24

alkali metals

Back 24

first column- for example K,-Na)

Front 25

alkali earth metals

Back 25

second column (Mg, Ca)

Front 26

noble gases

Back 26

elements of the 8th column that do not form compounds readily

Front 27

atomic interaction

Back 27

explained by periodic table and bohr; when two atoms interact their outermost shell electrons dictate their interatctions and thus govern their bonding properties.

Front 28

metals

Back 28

most of the table is metals, conducts electricity well

Front 29

pauli exclusion principle

Back 29

no two electrons can occupy the same energy state(level and position in that level) at the same time.

Front 30

structure of electron shells

Back 30

there are naturally occurring spaces in the electron shells that can be filled by electrons as determined by spacing and electron spin

Front 31

shells

Back 31

1st-2 spaces
2nd shell-8 spaces
3rd shell-8 spaces
4th- 18 spaces
5th-18 spaces
6th-32 spaces
7th(highest)-32

Front 32

rows

Back 32

1-2 spaces
2-8 spaces
3-8 spaces
4-18 spaces
5-18 spaces
6-32 spaces
7-32 spaces

Front 33

atomic mass

Back 33

(atomic mass)=mp+mn
mass of atom is found by adding mass of each proton and each neutron present in the nucleus.

Front 34

electrons in outer shell

Back 34

valence electrons

Front 35

chemical bonding

Back 35

commonly involves exchange or sharing of valence electrons

Front 36

valence-

Back 36

number of elctrons in the outer shell; also the combining power of atoms

Front 37

inert gases

Back 37

(noble gas) most stable arrangement of lowest energy because all shells are filled with electrons.

Front 38

quest of the atom

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to achieve the lowest energy state it can; so when atoms come near each other they may exchange or share electrons to achieve this state.

Front 39

chemical bond

Back 39

the result of redistribution of electrons that leads to a more stable configuration between two or more atoms

Front 40

strategies of atoms

Back 40

give up electrons
gain electrons
share electrons

Front 41

result of bonding

Back 41

spontaneous- a release of energy
due to outside energy-may release or absorb energy

Front 42

Atoms that are close to noble

Back 42

1 less- H, F, Cl
1 more- Li, Na, K, Rb
tend to form ionic bonds

Front 43

mettalic bonds

Back 43

bonds between metals; atoms float in a sea of electrons, many highly compressed gases can act as metal(O),

Front 44

alloy

Back 44

two or more metallic elements combined in a metalic bond.

Front 45

malleability

Back 45

a property of metals that allows atoms to rearrange themselves within the metallic bond to order to attain a new configuration in response to stresses; metals can be bent, shaped, molded due to this property.

Front 46

covalent bonds

Back 46

molecules that share electrons

Front 47

single bond

Back 47

one electron from each atom is shared

Front 48

the carbon bond

Back 48

the basic bond of all essential of molecules of life on earth. C atom config means it is equally likely to gain or lose 4 electrons

Front 49

the carbon-carbon system

Back 49

lower energy results from sharing of outer electrons with up to 4 other C atoms.

Front 50

organic chem

Back 50

study of C bonding and related bonding

Front 51

long chains of C and other atoms

Back 51

proteins, DNA, fats, cholesterol, etc.

Front 52

polar molecules

Back 52

molecules with either a positive or a negative side to them

Front 53

polarization

Back 53

electrons of neighbor atoms or molecules tend to be pushed away from a positive side of water; polarization makes substances like water act as a solvent(materials more easily disolves

Front 54

hydrogen bonds

Back 54

weak electrical attraction developed by the H atom itself after it is bonded to another element, like O or N

Front 55

Source of the force

Back 55

all charged parts of an atom exert electrical forces on all other neighbor atoms, so even if all atoms in a substance are electrically neutral and or non polar, the sum of the electrical charges within all atoms.

Front 56

gases

Back 56

collections of atoms or molecules that expands to take shape of and fill the volume available in a container

Front 57

atomic movement

Back 57

random bouncing off one another

Front 58

plasmas

Back 58

seas of electrically charged particles, properties can be confined by a magnetic field; conducts electricity; can grade into a gaseous state.

Front 59

liquids

Back 59

collections of atoms or molecules that have no fixed shape but maintain volume.

Front 60

water

Back 60

most common liquid on earth, but rare on other planets as far as we know.

Front 61

solids

Back 61

all materials that possess a more or less fixed ahpe and volume

Front 62

crystals

Back 62

groups of atoms that occur in a regularly repeating sequence farming a structure in which atoms or molecules occur in a regular and predictable way.

Front 63

unit cell

Back 63

the smallest subdivision of a crystal that shows the complete repeating pattern of atoms within the crystal.

Front 64

crystalline solids

Back 64

composed of interlocking crystals
natural: rocks(such as granite)
man-made- alloys and ceramics
organic: teeth, bones

Front 65

glass

Back 65

groups of atoms that are may be regular on a local scale, but are not regularly distributed throughout the solid.

Front 66

polymers

Back 66

long and large molecules that are formed from numerous smaller molecules; regular pattern of atoms in one direction

Front 67

plastics

Back 67

made of intertwined polymers derived from petroleum

Front 68

liquid crystals

Back 68

an odd intermediate state of matter that is half way between liquid and crystalline solid- man made

Front 69

changes of state in matter

Back 69

freezing and melting- changes between liquid and solid

Front 70

boiling and condensation

Back 70

changes between liquid and gas

Front 71

sublimation

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change from solid to gas

Front 72

driving force: temp

Back 72

transitions result from temp changes

Front 73

chemical reactions

Back 73

atoms and molecules coming together to form larger structure or larger structures breaking apart
reactants goes to products

Front 74

exothermic

Back 74

reactions that give off energy wile it occurs. when atoms or molecules combine the total energy is less, heat or light is given off

Front 75

endothermic

Back 75

reactions that take in energy while it occurs; when atoms or molecules combine the total energy is more so energy is absorbed

Front 76

oxidation

Back 76

giving up e- to oxygen

Front 77

combustion

Back 77

rapid oxidation reaction

Front 78

reduction

Back 78

chemical reaction in which electrons are transferred to an atom from other elements

Front 79

smelting

Back 79

reducting iron by heating in the presence of CO to make
F +CO2

Front 80

precipitation

Back 80

solids forming as a liquid evaporates or due to saturation in the liquid by a dissolved compound

Front 81

solution

Back 81

dissolving of solids into a liquid to dispered ions in a solution

Front 82

acid

Back 82

any material that when put in water produces positivly charged H ions in the solution

Front 83

base

Back 83

any material that when put in water produces negatively charged OH- ions

Front 84

acid-based reaction

Back 84

when two are brought together, water is formed

Front 85

acid and base with pH

Back 85

below 7 on ph scale base is above 7