1020 Chemistry Chap 2 Pt1

Front 1

Law of conservation of matter

Back 1

mass is neither destroyed nor created

Front 2

law of constant composition or law of definite proportions

Back 2

different samples of the same compound always contain its constituent elements in the same proportion by mass

Front 3

dalton's atomic theory

Back 3

an element is made up of atoms, and atoms of a given element are identical. Atoms cannot be destroyed or created(law of conservation of matter). All atoms of one element have the same size, mass and property. Atoms of two different elements have different sizes, masses and properties. Atoms of different elements may combine in simple, whole-number ratios to form compounds(Law of constant compostion) In chemical reactions, atoms are combined, separated, or rearranged

Front 4

Atom literally means

Back 4

uncuttable

Front 5

atoms are composed of

Back 5

protons, neutrons and electrons

Front 6

protons, neutrons and electrons are (this type of particle)

Back 6

subatomic particles

Front 7

much of our information about the structure of the atom comes from studies using

Back 7

cathode ray tube

Front 8

cathode ray

Back 8

stream of electrons that flow from negative electrode (cathode) to positive electrode (anode)

Front 9

the important characteristics of the subatomic particles are their

Back 9

mass and charge

Front 10

unit for atomic mass unit

Back 10

1.66 X 10^-24g

Front 11

Charges are expressed relative to the

Back 11

charge of an electron, which is given the value of -1

Front 12

Subatomic particles have very small masses, their masses are given in

Back 12

atomic mass unit or amu

Front 13

1 amu =

Back 13

1/12 of the mass of a carbon-12 atom (has 6 protons and 6 neutrons)

Front 14

a carbon-12 atom has a mass of

Back 14

exactly 12 amu

Front 15

the masses of all other elemental atoms are given..

Back 15

relative to the mass of carbon-12 atom.

Front 16

the relationship of amu to grams is

Back 16

1amu=1.661 X 10^-24g

Front 17

nuclear model of an atom

Back 17

mostly empty space, three subatomic particles make up all atoms. atoms have no net charge, the number of e- outside the nucleus equals the number of p+ in the nucleus.

Front 18

all atoms of the same element have the same

Back 18

number of protons in the nucleus, known as the atomic number, Z.

Front 19

atomic mass can be closely estimated by

Back 19

the sum of the masses of protons and neutrons Mass number = #protons + #neutrons

Front 20

isotopes are

Back 20

atoms with the same atomic number(Z) but different mass number(A). These are atoms of the same elements(have the same number of protons) but different in their number of neutrons

Front 21

atoms of an element are not identical....

Back 21

some atoms have more mass than others of the same element

Front 22

Isotopes can be represented by a

Back 22

nuclear symbol or mass numbers

Front 23

most elements have two or more

Back 23

isotopes

Front 24

Atomic mass(or atomic weight) is

Back 24

the weighted average mass of all isotopes of an element as they occur in nature

Front 25

element properties are periodic functions of their

Back 25

atomic numbers

Front 26

periodic table is organized in two specific ways

Back 26

increasing atomic number. Similar chemical/physical properties

Front 27

periodic table. groups or families

Back 27

vertical columns

Front 28

elements in the same group exhibit similar

Back 28

chemical and physical properties

Front 29

periodic table. Horizontal rows

Back 29

periods

Front 30

A and B groups on periodic table

Back 30

a is main group elements. B groups are transition elements

Front 31

the periodic table can be most easily separated into three sections

Back 31

metals, non-metals, and metalloids

Front 32

characteristics of metals

Back 32

lustrous appearance
mostly solids that are malleable(shapeable)
excellent electrical and thermal conductors
tend to form (+) ions in ionic compounds

Front 33

characteristics of non-metals

Back 33

dull appearance
wide diversity in physical states with solids being brittle or soft
poor electrical and thermal conductors(great insulators)
tend to form (-) ions in ionic compounds

Front 34

alkali metals(except H)

Back 34

react strongly with water to produce hydrogen gas and alkaline solutions.
only found as parts of compounds never as free elements

Front 35

alkaline earth metals(except Be)

Back 35

elements and their oxides also react with water to form alkaline solutions, thus they are known as "alkaline earth" metals

Front 36

halogens

Back 36

these are all reactive elements that generally exist in their elemental form as diatomic molecules

Front 37

noble gas(rare gases)

Back 37

least reactive elements
very low abundance on earth

Front 38

transition elements

Back 38

this block of metals contains some of the most useful and abundant elements Fe, Au, Cu

Front 39

actinides and lanthanides

Back 39

two heavy metal series sandwiched inside the transition elements block
contain well-known radioactive elements such as U, Pu

Front 40

compounds

Back 40

combination of two or more elements in definite ratios by mass

Front 41

the properties of each element are _____ when forming a new compound

Back 41

lost

Front 42

compounds can be decomposed into two or more

Back 42

different pure substances

Front 43

molecule

Back 43

the smalles unit of a molecular compound that retains the characteristics of the compound

Front 44

chemical formulas

Back 44

symbols used to describe the composition of compounds H2O

Front 45

at common temperatures __________ exsist as _______

Back 45

7 elements, diatomic molecules
H2, N2, O2, F2, Cl2, Br2, I2

Front 46

molecular formula

Back 46

tells the composition of a molecular compound, gives no structural info

Front 47

more than one compound may have the same

Back 47

molecular formula
ethanal C2H6O
dimethyl ether C2H6O

Front 48

Structural formula

Back 48

contains additional information (functionality) to help distinguish compounds of identical molecular formulas
ethanol CH3CH2OH
dimethyl ether CH3OCH3