unit 1A Flashcards
(130 cards)
1
Q
pure substance
A
a substance in which all particles making up the substance are the same
2
Q
element
A
is a pure substance that is made of atoms and cannot be broken down into simpler substances
eg gold, carbon, sulphur
3
Q
compound
A
a pure substance that is made of two or more atoms combined in a fixed proportion
4
Q
mixture
A
a substance in which there are two or more types of particles
5
Q
homogentous mixutre
A
a mixture inwhich particles are uniformly scattered only one phase is visible eg coffee
6
Q
heterogenous mixture
A
a mixture in which the particles are not uniformly scattered and therefore have more than one phase eg trail mix
7
Q
Examples of Empirical data: (6)
A
- Mass (g, kg, mg)
- Colour
- Volume (mL, (cm^3), L(dm^3))
- Melting point / Boiling point
- Phase (aq, s, l, g)
- denisity (g/ML)
8
Q
Empirical Knowledge
A
Things we learn or know through EXPERIENCE, EXPERIMENTATION, OBSERVATION or MEASUREMENT
Verifiable, factual information or knowledge
(things we can measure)
9
Q
What is Theoretical Knowledge
A
- Ideas or information we learn or understand that EXPLAIN that which we measure, observe, etc
- Theories explain data in a RATIONAL and TESTABLE way
(explain why things are the way they are)
10
Q
Example of Theoretical Knowledge
A
ATOMIC THEORY: our explanation of the properties of matter
11
Q
Example empirical definition of element - based on observations
A
A pure substance the CAN NOT be further broken down by ordinary chemical means (burning or running electricity)
12
Q
Example of of theoretical definition of element - explains observations
A
A pure substance that is COMPOSED OF ONLY ONE TYPE OF ATOM
13
Q
Example of Empirical Definition of compound - based on observations
A
A pure substance that CAN be broken down into difference substances by ordinary chemical means ( burning or running electricity)
14
Q
what are physical properties? give examples of properties
A
They are measured or observed without changing the identity of the substance or matter in an object. Physical properties are how metals/nonmetals are generally classified.
eg. density, mass, color, conductivity, solubility, melting point/boiling point
15
Q
Example of Theoretical Definition of compound - explains observations
A
A pure substance that is COMPOSED OF TWO OR MORE SUBSTANCES that are chemically bonded together
16
Q
What are properties
A
properties of a substance are those CHARACTERISITS that are used to IDENTIFIY, DESCRIBE and/ or determine its UTILITY
17
Q
what are chemical properties?
A
they describe how a substance typically BEHAVE in a chemical reaction with another substance. Chemical properties are characteristics with chemicals GROUPS or FAMILY
eg combustion, synthesis, single displacement, double displacement, decomposition
18
Q
What are the clues of a chemical reaction
A
CHBS
C- new or unexpected colour appears
H - heat or light is given off
B - appearance of bubbles means a gas might have been produced
S - Solid (precipitate) appears cloudy
A NEW SUBSTANCE APPEARS
19
Q
What is quantitative?
A
those properties we can measure (have units)
eg 50.0
20
Q
\what is qualitative
A
those properties we observe but do not measure
eg odorr
21
Q
what does IUPAC stand for and what does it resposable for
A
Internation Union of Pure and Applied Chemists
Responsible for setting INTERNATIONAL STANDARDS in the fields of chemistry
Units, nomenclature and names of new elements are examples
22
Q
what does SATP stand for
A
Standard Ambient Temperature and Pressure
25C (298K) and 100kPa (1 atm)
23
Q
what does STP stand for
A
Standard Temperature and Pressure
0C (273K) and 101.325 kPa
24
Q
what are the diatomic elements and phases?
A
the DIabolical gang of HOBrFINCl
H2(g) O2(g) Br2(L) F2(g) I2(s) N2(g) Cl2(g)
with their leader SULtry OCTavia
S8(s)
and her sidekick 4-fingered Pete
P4(s)
25
what is the modern periodic law
when elements are arranged in order of INCREASING ATOMIC NUMBER, Z there is PERIODIC RECURRENCE and GRADUAL CHANGE in both PHYSICAL & CHEMICAL PROPERTIES
26
how many periods are there? and which way is it
seven horizontal periods ( inner transition metals belong to period 6 and 7)
27
how many groups are there? and which way is it>
verical groups of 18
28
what is the staircase?
"under the bum of boron and stepwise down"
broadly separates metals form nonmetals
29
what are syntheic elements?
they are made my humans
30
what are transuranic elements
are synthetic elements and are RADIOACTIVE. That means there are 90 naturally occurring elements
31
what are physical properties of metals
- silver or grey in colour
- very high melting point/boiling point
- conductive of heat and electriesty
- shiny
- malleable
- ductile
- SOLID at SATP
32
what are physical propers of nonmetals
- different colours
- lower melting point/boiling point
- do not conduct heat or electriesty
- dull and brittle
- not malleable
- not ductile
- can be solid liquid or gas at SATP
33
what are represtnative elements
have predictable empirical properties and chemical behaviours metals are MONOVALENT
valence electrons can be determined from group number
S BLOCK AND P BLOCK
34
H
group 1 can gain. lose or share valence eletrons
35
Alkali metals
group 1 metals: MOST reactive metals, soft
36
alakaine earth metals
group 2 elements, reactive metals, harder
37
halogents
group 17 most reataive nonmetals
38
noble gases
group 18 chemcially stable
39
transition metals
groups 3-12
most are bi or mulivalent
D BLOCK
40
Inner transition metals
belong or period 6 and 7
F BLOCK
41
Democritus
- first atomic theory of matter
- "all matter could be divided into smaller and smaller pieces until a single indivisible particle was reached" False
- there is empty space between atoms
42
aristole
- all atoms are made of air, earth, fire, or water
- diff combos = diff qualities (dry hot, cold, and moist)
43
john dalton
- atoms are neither created or destroyed in a chemical reaction
- there will be no change in mass in a chemical reaction
- atoms can join another but never destroyed
- all matter is composed of tiny, indivisible particles called atoms
44
JJ thomson
- used a modified cathode tube to measure the mass of the particle & its electric charge
- hypothesize the existence of electrons
- suggested that negative charged electron are distributed inside the atom
45
ernest rutherford
- 2 types of radiation, alpha & beta particles
- believed that atoms must contain a nucleus (positively charged) and which is surrounded by electrons
46
henry mosely
- he arranged the elements of the periodic table according to atomic number
- proved that each element is defined by number of protons and charge in the number changes the element of the atom
47
neils bohr
- proposed a theory based on quantum theory that some physical qualities only take discrete values
- first to discover that electrons travel in separate orbits around the nucleus
- number of electrons determine properties of element
48
james chadwick
- discovered the neutron
- conducted an experience creating radioactive decay discovering the neutron
49
what is the order of the e levels?
n1= 2
n2 = 8
n3 = 8 (fill to 8 then 2 in n4 then fill to 18)
n4 = 32
50
what is standard nuclear notation?
mass number on top (A) (A= Z + N)
atomic number on bottom (Z)
eg
A(top)
X
Z (bottom)
51
wht is an atom
neutral same number protons and electrons defined by 2
52
what is an ion
charged net charge produced by gain or lose of electrons
53
what is isotopes ?
- a form of an element with a specific number of neutrons
- elements may only 1 naturally occurring isotope or several
- different isotopes have different numbers of neutrons an different mass numbers
- all isotopes of the same element have the same number of protons and the same atomic number
54
what is mass number? (A)
- is the protons plus neutrons of a specific isotope
- whole number always
- the A for the most common istope can be determined by rounding the average atomic mass on the periodic table
55
what is the average atomic mass (Ar)
- is the average relative mass of all naturally occurring isotopes including the relative mass of electrons weighted average decimal places
56
isotope notation
C-12
C = element symbol (which then can find the atomic number)
12 = mass number (whole number protons + neutrons )
57
law of conservation of mass
THE TOTAL MASS OF REACTIONS IS EQUAL TO THE TOTAL MASS OF PRODUCTS IN A CHEMICAL REATCIOTN
( mas is conserved in a chemical rzn)
58
Law of constatnt compostion
compounds always have the same percentage composition by mass
59
what is a radioisotope?
- a radioactive isotope of an element, occurring naturally or produced artificially (synthetic element)
- spontaneously emits radiation (light energy) as unstable nucleus decays
60
what is radioactive
- capable of spontaneously emitting radiation in the form of particles and/or gamma rays
61
Alpha, α
- has the same mass and charge as a helium nucleus
4 2+
He
2
- 0.05 x 3.00 x 10^8 ms-1
- 0.05 speed of light (54 million km/h)
- penetration: a few cm in the air
- effective barrier: a piece of paper
62
alpha rationation
- an alpha particle has the same mass and charge as a helium nucleus
- one example of alpha particle emission is the decay of radium
226 4 222
Ra -----> α + Rn
88 2 86
63
beta, β
- mass the same mass and charge as an electron
- relatively fast with variable speed, typical 30 to 98 times the speed of light
- penetration: a few meters in air
- effective barrier: 1-2 millimeters of metal
0
β
-1
64
beta radiation
- a beta paricle has the same propers as an electomr
- one example of beta particle emisson is the decay of carbon -14
14 0 14
C -------> β + N
6 -1 7
65
gamma γ
- has no mass or change, pure energy
- very fast, the speed of light
- penetration: unlimited, in the air
- effective barrier: 1 metre of lead
0
γ
0
66
gamma radiation
- gamma radiation is high energy radiation, it often accompanies either alpha or beta radiation
- one example of gamma emission is the decay of cesium-137
137 0 0 137
Cs ----> β γ Ba
55 -1 0 90
67
Half-life
- the time it takes of one-half the nuclei in a radioactive sample to decay
mf=mi(½)^n
mf= final mass
mi = initial mass
n = number of half-lives
68
non medical uses of radiation
- power/energy
- smoke detectors
- C-14 dating dinosaurs
69
medical uses of radiation
- treatment of cancers
- diagnostic imaging (MRI, CT, x-ray)
70
what is n=1/the lowest energy state also known as?
GROUND LEVEL
71
what is a photon
tiny particle of light
72
what absorption?
when the electron ABSORBS a photon, it becomes excited to a HIGHER ENERGY LEVEL
we do not see this because energy is being absorbed by the atom
if an electron absorbs energy it will move from a lower energy level to a higher energy level
73
what emission?
when a not stable electron RELEASES or emits a photon, it moves from a HIGHER ENERGY LEVEL to a LOWER energy level
we can detect this because energy is being emitted
if an electron releases/loses energy it will move from a higher energy level to a lower energy level
74
what did bohr suggest
only certain energy levels are possible
he called it stationary states because the ENERGY of the electron remained constant
electrons in higher energy levels have more energy
the e levels get closer together as the value of n increases
75
energy levels
all electrons of the same energy belong to the same e levels and from an electron shell
each energy level may accommodate a maximum number of electrons given by the expression 2n^2
76
what are valence electrons
electrons found in the outer most energy level of an atom
the number of valence electrons corresponds to the last digit of the group number on the periodic table for the representative elements (S & P block)
77
what are valence electrons
electrons found in the outer most energy level of an atom
the number of valence electrons corresponds to the last digit of the group number on the periodic table for the representative elements (S & P block)
78
what are core electrons
electrons between the outermost energy level and the nucleus
79
what does the number of occupied energy levels correspond to?
the period in which the atom is located
80
how to to calculate n for S and P block?
n = period number for s and p block
81
how to to calculate n for D block?
n = period number - 1
82
how to to calculate n for F block?
n = period number - 2
83
points to remember for modern atomic theory
- the number of ve- correspond to the last digit of the group # for the representative elements
- the # of occupied E-levels corrections to the PERIOD NUMBER
- the Bohr model only works perfectly for Hydrogen
- B-R diagrams are valid for or Z=1-20
84
what are orbits
the circular path in which an electron can move around the nucleus
85
what is transition
movement of an electron from one energy level to another
86
line spectrum
(light) emitted consists of a series of sharp lines
87
continuous spectrum
all of the values in the spectrum without any gaps, skips, or breaks
88
wht is the concpet of the atom
nuclear force an attractive force within the nucleus for the force of repulsion
89
what is electron behaviour
an electron can travel indenitintity within an energy level without losing energy
the greater the distance between the nucleus of the atom and the energy level, the greater the energy required for an electron to travel in the energy level
90
what is the effeictive nuclaer charge
the net nuclear charge on Ve- when Ce- are takin into account
Zeff = Z-(Z- group #)
91
what si shielding effect
caused by Ce- and the number of E levels they occupy
basically the negative charges and distance shielding the attraction between the positive nucleus and the negatives ve-
92
what are considerations of core electrons for shielding effect
affects magnitude of charge shielding Ve- from Z
all else being equal, more Core electrons = higher shE = weaker nuclear hold on Ve-
93
how does Zeff change as you move DOWN A GROUP. Explain
it is CONSTANT as one goings down a group of representative elements because the overall PULL the nucleus has for Ve- is the same for all the elements in the group
94
how does Zeff change as you move ACROSS A PERIOD
it INCREASES as one goes ACROSS A PERIOD meaning the overall PULL the nucleus has for the Ve- increases as one moves from L to R across a period
95
how does ShE change as one moves DOWN A GROUP
ShE INCREASES meaning the attraction the nucleus has for Ve- is shielded more as one going down a group
96
how does ShE change as one moves ACROSS A PERIOD
ShE remains CONSTANT meaning all atoms have similar effect of the nucleus
97
what does Zeff:ShE ration mean
LOOKING at these forces as a RATIO of opposite force allows us to compare the hold an atom has on its Ve-
Zeff - the overall the Ve- experiences toward the nucleus
ShE - the overall SHIELDING/INTERFERENCE the Ve- experience doone to CORE ELECTRONS and E LEVELS (distance)
98
which has a higher Zeff; ShE ratio: Li or Na
within a group
Na bc the denominator / is larger meaning the OVERALL Zeff/ShE is SMALLER
99
which has a higher Zeff; ShE ratio: Mg or Na
across a period
Na bc the denominator / is larger meaning the OVERALL Zeff/ShE is SMALLER
100
which has a higher hold on its Ve-: Mg or Na
Mg bc the HIGHER the OVERALL Zeff;ShE ration, the stronger hold on Ve- (really high Zeff and/or really low ShE)
101
what happens to the Zeff;ShE ratio as going ACROSS A PERIOD
it increases
102
what happens to the Zeff;ShE ratio as going DOWN A GROUP
it decreases
103
how does reactivity affect metals going DOWN a GROUP
it INCREASES
104
how does reactivity affect metals going ACROSS a PERIOD
it DECREASES
105
how does reactivity affect nonmetals going DOWN a group
it DECREASES
106
how does reactivity affect nonmetals going ACROSS a PERIOD
it INCREASES
107
metals and non mentals octet
metals tend to LOSE Ve- to reveal an underlying stable octet because they tend to have a weather holden their Ve- AND nonmetals tend to GAIN Ve- to obtain a stable octet because they tend to have a stronger attraction for Ve-
108
what does this mean in terms in hold on Ve- and reactiveity of metals and nonmetals?
the stronger the hold on Ve- the more REACTIVE NONMETALS are and the LESS REACTIVE METALS are
- The weaker the hold on Ve- the LESS REACTIVE NONMETALS are and the MORE REACTIVE METALS ARE
- Zeff/ShE higher = stronger hold
- Zeff/ShE lower = weaker hold
109
atomic radius Ar
all atoms have no definite surface, bonded atoms in molecules are like touching spheres
atomic radius is one-half the distance between the nuclei of two atoms of the same element, whether they are bonded or not bonded
110
how does atomic radii change down a group?
it INCREASES
The Zeff is constant going down a group , but the ShE increases, meaning the Zeff to ShE ratio DECREASES, meaning the nucleus has a weaker hold on its Ve- as one moves down a group. A weaker hold means larger radius
111
how does atomic radii generally change across a period
As one moves across a period the Zeff INCREASES but the ShE remains constant meaning the Zeff to ShE ratio INCREASES, meaning the nucleus has a stronger hold on it's Ve-. A stronger hold means a smaller radius
112
CATIONS are _____ than the partent atom
SMALLER
Zeff increases and She decreases meaning Zeff/She increases meaning a stronger hold on its Ve- meaning a smaller radius for the cation than its parent atom
113
ANIONS are _____ than the parent atom
LARGER
Zeff constant and She constant meaning Zeff/She doesn't not change meaning the hold on Ve- isthe same but has to be disbrioused over more e- meaning a slighly larger radius for the anion than its parent atom
114
what does ISOELECTRONIC mean
same electron arrangement
radii within an ISOELECTRONIC are affected by a changing Zeff, while ShE is constant; the electron configuration for all elements in a ISOELECTRONIC series is the same
115
what is ionization energy
the energy required to REMOVE an e- from a neutral gaseous atom
is the measure of how tightly e- are held in place
when we compare:
1) 1st IE of 2 elements
2) successive IE's for the same element
116
what is the formula for ionization energy
X(g) + ENERGY ---> X+(g) + e-
117
how does ionization change as one proceed DOWN a group
IE is the measure of how strongly attract Ve- are to their atoms. Zeff is constant going down a group , while She increases means that the Zeff to ShE decreases, meaning that the hold on the Ve- becomes weaker. It would take less energy to remove a Ve-g
118
how does ionization change as one proceed ACROSS a period
IE is the measure of how strongly attract Ve- are to their atoms. Zeff is increases going across a period, while She remains constant means that the Zeff to ShE increases, meaning that the hold on the Ve- becomes stronger. It would take more energy to remove a Ve-
119
what is electron affinity
is the energy change that occurs as neutral atoms in the gaseous state GAINS an e-
is a measure of how tightly electrons are held by an atom
120
what is the formual for elctrom affinity
X(g) + e- --->X- (g) + ENERGY
121
how does e-A generally change as one proceeds down a group
electron affinity is the measure of how strongly atttarcted Ve- are held to their atom Zeff remains constant going down a group , while ShE increases, meaning that the Zeff to ShE ratio decreases. MEaning the attraction an atom has for its Ve- becomes weaker so the electron affinity would be less
122
how does E-A generally change as one goes ACROSS A PERIOD
electron affinity is the measure of how strongly attracted Ve- are held to their atom Zeff increases , while ShE remains constant, meaning that the Zeff to ShE ratio increases. MEaning the attraction an atom has for its Ve- becomes stronger so the electron affinity would be more
123
what is electronegativity
the ability of an atom to attract Ve- when in a bond with another atom
124
what does EN of 0.0-0.4 indicate
a nonpolar covalent bond
125
what does EN of 0.5-1.7 indicate
a polar covalent bond
126
what does EN of 1.8 or higher indicate
an ionic bond
127
what does polar mean
ends
128
what does nonpolar mean
balance
129
how does electronegativity change as one GOES DOWN A GROUP
electronegativity measures how strongly attached valence electrons are to their atom. Zeff remains constant, while ShE increases, this means a lower Zeff to she ratio therefore the attraction that the valence electrons has to its atom this means that the electronegative would be less.
130
how does electronegativity change as one goes ACROSS A PERIOD
elecronegaticy measures how strongly attracted valence electrons are to their atoms. Zeff increases while she remains constant, therefore the Zeff to she ratio increases means that the zeff to share ratio would increase meaning that the attraction that he valence electrons has to its atom is higher
