Unit 3 Flashcards
(81 cards)
1
Q
element
A
a substance that can’t be broken down into other substances by chemical methods
microscopic form - sometimes used to mean a single atom of that element
macroscopic form - other times used to mean a sample large enough to weigh on a balance
generic form - when we say human body contains sodium, doesn’t mean elemental sodium is present, rather atoms of some form of sodium; many r soluble
118 elements, 88 of which occur naturally
2
Q
chemical symbols
A
used as abbreviations for element names
if 3 letters = unknown
3
Q
Al
A
Aluminum
13
4
Q
Ar
A
Argon
18
5
Q
Ba
A
Barium
56
6
Q
B
A
Boron
5
7
Q
Br
A
Bromine
35
8
Q
Ca
A
Calcium
20
9
Q
C
A
Carbon
6
10
Q
Cl
A
Chlorine
17
11
Q
Cr
A
Chromium
24
12
Q
Co
A
Cobalt
27
13
Q
Cu
A
Copper (cuprum)
29
14
Q
F
A
Fluorine
9
15
Q
Au
A
Gold (aurum)
79
16
Q
He
A
Helium
2
17
Q
H
A
Hydrogen
1
18
Q
I
A
Iodine
53
19
Q
Fe
A
Iron (ferrum)
26
20
Q
Pb
A
Lead (plumbum)
82
21
Q
Li
A
Lithium
3
22
Q
Mg
A
Magnesium
12
23
Q
Mn
A
Manganese
25
24
Q
Hg
A
Mercury (hydrargyrum)
80
25
Ne
Neon
10
26
Ni
Nickel
28
27
N
Nitrogen
7
28
O
Oxygen
8
29
P
Phosphorus
15
30
Pt
Platinum
78
31
K
Potassium (kallium)
19
32
Si
Silicon
14
33
Ag
Silver (argentium)
47
34
Na
Sodium (natrium)
11
35
Sr
Strontium
38
36
S
Sulfur
16
37
Ti
Titanium
22
38
Zn
Zinc
30
39
Dalton's Atomic Theory
1. Most natural materials are mixtures of pure substances.
2. Pure substances are either elements or compounds
3. law of constant composition
1. Elements are made of atoms
2. All atoms of a given element r identical
3. the atoms of a given element r diff from those of any other element
4. atoms of 1 element can combine with atoms of other elements to form compounds.
40
compounds
a distinct substance that is composed of the atoms of 2+ elements & always contains exactly the same relative masses of those elements
can be broken down into elements by chem methods
always has the same relative #'s & types of atoms
41
law of constant composition
a given compound always contains the same proportions (by mass) of the elements.
Ex: water always contains 8g of oxygen for each gram of hydrogen
42
atoms
tiny particles of which elements are made
indivisible in chem processes
not created/destroyed in chem reactions. reaction only changes the way the atoms r grouped together
43
chemical formula
expresses the type of atoms & #'s of each atom in a given compound
table salt = NaCl
water = H2O
44
chemical name
table salt = sodium chloride
45
electron
a negatively charged particle
located outside of nucleus in a negatively charged "cloud"
most of volume of atom
46
proton
a positively charged particle, same size of charge as an electron, but positive
47
neutron
a neutral particle w/ a mass relatively close to that of proton
48
nucleus
small dense center of atom
protons & neutrons
most of the mass of atom
49
why do diff atoms have diff chem properties?
the # & arragnement of the electrons
the space in which the electrons move accounts for most of the atomic volume. the electrons r the parts of the atoms that intermingle when atoms combine to for molecules. the # of electrons a given atom possesses greatly affects the way it can interact w/ other atoms
50
atomic number
the identity of an element is determined by this
the # of protons
51
isotopes
(of an element)
have the same # of protons, & therefore the same atomic #, but diff #'s of neutrons
52
mass number
the total # of protons & neutrons in an atom
used in naming to identify isotopes, such as Carbon-14 & Carbon-12
53
practical purpose of isotopes
Iodine-123 (half-life 13 hours) is the isotope of choice for nuclear medicine imaging of the thyroid gland, which naturally accumulates all iodine isotopes
54
metals
good conductors of heat & electricity
shiny
malleable
ductile
always form cations; tendency to lose electrons = a fundamental characteristic of metals
55
shiny
have luster
56
malleable
can be hammered into sheets
flattens/bends w/out shattering
57
ductile
can be drawn into wires
58
comparison of electron models
59
nonmetals
good insulators
dull appearance
most r gases/easily vaporized solids & liquids
solids r brittle
60
insulator
absorbs electricity
61
metalloids
exhibit some prop's of both metals & nonmetals
62
groups
all elements in a group have similar chem prop's
63
Group 1
Alkali Metals
64
Group 2
Alkaline Earth Metals
65
Groups 3-12
Transition Metals
66
Group 17
Halogens
67
Group 18
Noble Gases
68
diatomic molecules
cannot stand alone
2 atoms
hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine
HINClBrOF
69
ions
the equal # of protons & electrons gives an atom a net zero charge
adding or removing an electron from a neutral atom will create a charged ion
always fromed by adding/removing electrons, not by changing the # of protons
70
cation
positive ion
when atom loses 1+ electrons
Na → Na+ + e-
named using name of the parent atom
Ex: Na+ is called the sodium ion
71
anion
negative ion
when an atom gains 1+ electrons
Cl + e- → Cl-
named by taking the root name of the atom & changing the ending (adding -ide)
72
common anion name changes
chlorine - chloride ion
flourine - flouride
bromine - bromide
iodine - iodide
oxygen + 2 electrons = oxide
sulfur + 2 electrons = sulfide
73
ion group charges
Group 1 metals - +1
Group 2 metals - +2
many Group 3-12 metals - multiple charges
Group 13 metals - +3
Group 16 atoms - -2
Group 17 atoms - -1
74
ionic compounds
whenever a compound is formed b/w a metal & non-metal, it can be expected to contain ions
usually formed when metals + nonmetals; when they react, the metal atoms tend to lose 1+ electrons, which r gained by the atoms of the nonmetals; the reactions tend to form compounds that contain metal cations & nonmetal anions
chem compounds must have net charge of 0 - must be cations & anions present; the # of cations & anions must result in net charge of zero
usually strong electrolytes & can be expected to dissociate completely in solution
75
rules for compound formula writing
the cation/metal/pos. is always written first
use subscripts to balance charges on compounds
76
brittle
shatters/cracks into small pieces when struck
77
strong electrolyte
a substance that separates into ions when dissolved in water
78
dissociation
the process in which ionic compounds separate into ions
79
molecular compounds
usually non-electrolytes & don't dissociate to form ions
resulting solutions don't conduct electricity
80
molecular acids
can partially/completely dissociate, depending on their strength
81
W
tungsten
74
