Quiz 2 (chapter 2-3) Flashcards
(118 cards)
1
Q
atom definition
A
the smallest identifiable unit of an element (invisible in greek)
2
Q
atoms are the key to?
A
connecting the macroscopic and microscopic worlds
3
Q
how many natural occurring and synthetic elements
A
91 natural
over 20 synthetic
4
Q
3 most important laws
A
law of conservation mass
law of definite proportions
law of multiple proportions
5
Q
Dalton’s?
A
atomic theory
6
Q
J.J. Thomson?
A
discovery of the electron with cathode ray experiment —> Thomson’s atomic model
7
Q
Milikan?
A
the charge of the electron with oil drop experiment
8
Q
Rutherford?
A
atomic model with gold foil experiment
9
Q
J.J Thomson conclusion?
A
the charge-to-mass ratio for the negatively charged electron ( -1.76 x 10^8 C/g)
10
Q
C?
A
Coloumb (unit for charge)
11
Q
u?
A
amu (atomic mass unit)
12
Q
Milikan conclusion?
A
the charge of the electron to be ( -1.60 x 10^-19 C)
13
Q
How do we deduce the mass of an electron?
A
with the charge of the electron and the mass-to-charge ratio
14
Q
Rutherford proposed the nuclear theory of the atom, what is part 1?
A
1) most of the atoms mass & all of its positive charge are contained in a small core called NUCLEUS
14
Q
Rutherford proposed the nuclear theory of the atom, what is part 2?
A
2) most of the volume of the atom is empty space, with tiny, negatively charged ELECTRONS dispersed
15
Q
Rutherford proposed the nuclear theory of the atom, what is part 3?
A
3) there are as many negatively charged ELECTRONS outside the nucleus as there positively charged PROTONS within the nucleus —> electrically neutral
16
Q
Rutherford’s model’s flaw?
A
James Chadwick demonstrated that the previously unaccounted for mass was the NEUTRONS (neutral particles in the nucleus)
17
Q
Mass & charge of neutron
A
mass= similar to proton
charge= no electrical charge
18
Q
Compare mass of Helium atom with Hydrogen atom
A
Helium is 4 times as massive as Hydrogen —> CAUSE it contains 2 protons & 2 neutrons
19
Q
atoms are composed with which subatomic particles?
A
protons, neutrons, electrons
*** with nearly identical masses
20
Q
number of protons defines?
A
the element
***most important number to identify
20
Q
atomic number?
A
number of protons (which is =number of electrons) in the atom’s nucleus (Z)
21
Q
***54 elements
A
22
Q
each element is identified by:
A
a unique atomic number with a unique chemical symbol
23
isotopes definition
atoms with the same # of protons but different # of neutrons (each with a slightly different mass)
24
mass number definition?
the sum of the number of neutrons and protons in an atom (only whole numbers) (A)
25
mass number equation?
A= # protons (p+) + # neutrons (n)
n= A - Z
26
chemical symbol?
element (X)
27
Isotope notation #1
A X
Z
(20 Ne )
(10 )
28
Isotope notation #2
X-A
(Ne-20)
29
Natural Abundance definition
relative amount of each different isotope in a naturally occurring sample of a given element is roughly constant (%)
30
% abundance equation
% abundance Ne-20 = X / (X + Y + Z) x100
31
ions definition
of electrons in a neutral atom = # of protons in its nucleus
***in chemical change, atoms can lose/gain electrons and become charged with particles (IONS)
32
cations?
positively charged ions (Na+)
33
anions?
negatively charged ions
34
equation to show for ions (gain and loss)
Mg ---> Mg^2+ + 2e^-
#e- 12 10
#p+ 12 12
N + 3e^- ---> N^2-
#e- 7 10
#p+ 7 7
35
Mendeleev's periodic law
when the elements are arranged in order of increasing mass, similar properties recurred in a periodically
36
Modern periodic table order?
increasing atomic number rather than increasing relative mass
36
Modern periodic table contains?
more elements than Mendeleev's table
37
***metal, metalloids, nonmetal
***
38
metals (L) common properties (6)
-good conductors of heat & electricity
-malleable (pounded into sheets)
-ductility (drawn into wires)
-often shiny
-lose electron
-form cation
39
metals exceptions (3)
-NOT Hydrogen
-all solid EXCEPT Mercury (liquid)
-including Al & Po
40
metalloids common properties (3)
-also called semimetals
-MIXED properties
-some are semiconductors
41
metalloids exceptions (1)
-NOT Al & Po
42
nonmetals (R) common properties (6)
-poor conductors of heat & electricity
-not malleable
-not ductile
-often shiny
-gain electron
-form anion
43
nonmetals exceptions (4)
-Including Hydrogen
-5 solids (C, P, S, Se, I)
-1 liquid (Br)
-11 gases
44
main-group elements?
properties tend to be predictable based on their position (not the middle ones)
45
transition elements?
properties tend to be less predictable based on their position (middle)
46
noble gas? (3)
-group 8A
-also called gas inert
-unreactive
47
alkali metals? (2)
-group 1A
-very reactive (create heat; in water)
48
alkaline metals? (2)
-group 2A
-fairly reactive
49
halogens? (3)
-group 7A
-very reactive nonmetals
-found in nature as a salt (ionic compound)
50
halogens phases? (4)
-F (gas)
-Cl (gas)
-Br (liquid)
-I (solid)
51
main-group metals tend to ?
lose electrons (forming a cation with same # electrons as nearest noble gas)
52
main-group nonmetals tend to ?
gain electrons (forming an anion with same # electrons as nearest noble gas)
53
alkali metals tend to? (1A)
lose 1 electron & form 1+ ions
54
alkaline metals tend to? (2A)
lose 2 electron & form 2+ ions
55
aluminum tends to? (3A)
lose 3 electron & form 3+ ions
56
halogens tend to? (7A)
gain 1 electron & form 1- ions
57
oxygen family nonmetals tend to? (6A)
gain 2 electron & form 2- ions
58
nitrogen tends to? (5A)
gain 3 electron & form 3- ions
59
atomic mass is also called
atomic weight or standard atomic weight
60
atomic mass represents?
the average mass of the isotopes that compose that element (weighted according to the natural abundance of each isotope)
61
atomic mass equation
Atomic mass (Σ) = (fraction isotope 1 x mass) + (fraction isotope 2 x mass)
***fraction isotope= % abundance
62
Mass spectrometer graph (3)
-amount of peaks= how many isotopes exist
-x-axis= accurate mass of each isotope in amu
-% abundance= X(height) / (X + Y) x 100
63
how to know the number of atoms?
weighing them
64
mole definition
the measure of the material containing 6.02214076 x 10^23 particles (1 mol=6.02214076 x 10^23 particles)
65
mole = value of atoms in ?
X grams (12 grams of C-12)
66
conversion factor of mol atoms --> atoms
1 mol atoms / 6.02214076 x 10^23 atoms
67
molar mass definition
the mass of 1 mol of atoms of an element
***molar mass (g/mol) = atomic mass units (amu)***
68
method to count # of atoms (3)
1) mass of element
2) convert into moles
3) convert into atoms (Avogadro)
69
mixture vs compound
mixture= elements can mix in any proportions whatsoever (H2, O2)
compound= elements combine in fixed, definite proportions (H2O, fixed amount of H and O)
70
compounds are composed of?
atoms held together by CHEMICAL BONDS
71
chemical bonds definition
result from the attractions between the charged particles (e- & p+) that compose the atoms
72
two types of chemical bonds?
ionic bonds and covalent bonds
73
1) ionic bonds definition
-bonds that occur between metals & nonmetals
-transfer of electrons from the metal atom & the nonmetal atom (cation & anion)
74
what happens to metal and nonmetal in an ionic bond?
-metal becomes a cation
-nonmetal becomes an anion
75
how an ionic bond forms?
the oppositely charged ions attract one another by electrostatic forces
76
in SOLID phases, ionic compound is composed of?
a lattice
76
crystal lattice (lattice)
3D array of alternating cations & anions
77
2) covalent bonds definition
-bonds that occur between 2 or more nonmetals
-transfer of electrons, composing a molecule
78
covalent bonds synonym
molecular compounds
79
compound's chemical formula indicates?
-the elements present in the compound
-the relative number of atoms/ions of each
80
3 types of chemical formulas
1) empirical formulas
2) molecular formulas
3) structural formulas
81
1) empirical formula?
gives the relative number of atoms of each element in a compound (divide by the greatest common factor) (H2O2 --> HO)
82
2) molecular formula?
gives the actual number of atoms in each element in the molecule of compound (as it is)
83
3) structural formula?
***check pictures***
-uses lines to represent covalent bonds
-shows how atoms in a molecule are connected/bonded to each other
(H--O--O--H)
84
which chemical formula communicates the most information?
structural formula
85
which chemical formula communicates the most information?
empirical formula
86
molecular model indicates?
a more accurate & complete way to specify a compound
87
4) ball-and-stick molecular model?
atoms as balls & chemical bonds as sticks (how the two connect reflects a molecule's shape)
87
5) space-filling molecular model?
atoms fill the space between each other to more closely represent a best estimate of how a molecule will appear if visible
88
molecular type of chemical formulas?
molecular models:
4) ball-and-stick model
5) space-filling model
88
elements can be?
atomic OR molecular
89
compounds can be?
ionic OR molecular
90
atomic elements?
exist in nature with single atoms as their basic unit
(all the noble gases & metals)
91
molecular elements?
do not exist in nature with single atoms, they exist as MOLECULES (2+ atoms of the element bonded together)
92
molecular element: diatomic elements? (7)
H2, N2, O2, F2, Cl2, Br2, I2
93
molecular element: polyatomic elements? (3)
P4, S8, Se8
94
molecular compounds are composed of?
2 or more covalently bonded nonmetals
95
basic units of molecular compounds?
molecules
96
ionic compounds are composed of?
cations (usually metal) & anions (usually nonmetal) bound together by ionic bonds (NaCl)
97
basic unis of ionic compounds?
formula unit
98
ions can be?
monoatomic ions OR polyatomic ions
99
polyatomic ions?
composed of a group of covalently bonded atoms with an overall charge
100
ionic compound formulas? (3)
1) always contain positive & negative ions
2) sum of cations = sum of anions
3) smaller whole-number ratio (simplify)
101
2 types of ionic compounds?
type 1: metal forms only 1 type of ion
type 2: metal forms many types of ion
102
Naming type 1 ionic compounds
**metal ion always have the same charge
name of cation + base name of anion (+ide)
(metal) (nonmetal)
103
***know metal ion charges & certain nonmetal
***
104
Naming type 2 ionic compounds
**metal can form 2+ kind of cation (must be specified/deduced)
name of cation (charge) + base name of anion (+ide)
(metal) (Roman numerals) (nonmetal)
105
***know metal ion charges that have diff charges
***
106
***charge of type 2 metals= determined by calculations
***
107
***Naming polyatomic ions
***
108
Oxyanions?
(most polyatomic ions are oxyanions)
=anions containing oxygen & another element
109
oxyanions= more oxygen atoms VS fewer
more oxygen= -ate (nitrate)
fewer oxygen= -ite (nitrite)
110
oxyanions= more than 2 oxygen VS less than 2
more than 2 oxygen= per- (perchlorate)
less than 2 oxygen= hypo- (hypochlorite)
111
hydrates?
ionic compounds containing a specific number of water molecules associated with each formula unit (x H2O)
112
***hydrate prefixes
***
