Chemistry Lesson 1 - 3 Flashcards

1
Q

What is Democritus theory?

A
  • That atoms are small hard particles
  • they are always moving
  • come together to make different material
  • in different sizes and shapes
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2
Q

What is Daltons theory?

A
  • elements are made of small, indivisible particles (unique to each element)
  • in chemical reactions: atoms sep, combine or rearrange in diff. ratios
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3
Q

What is Thomsons theory?

A
  • Did experiment on cathoray - saw that electrons repel each other
  • discovered electrons
  • made plum puddling model - electrons are spread apart and being surrounded with the pudding which is positive
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4
Q

What is Rutherfords theory?

A
  • gold foil experiment - found that the positive alpha particles are repelling the protons
  • dissolved protons and nucleus
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5
Q

What is Bohrs theory?

A
  • electrons can jump between orbitals by absorbing light photons
    Model of atom:
    Postulate 1 - electrons can move in a certain orbital, each corresponding to a specific energy level and where electron can move without LOSING ENERGY
    Postulate 2 - electrons can only move from 1 orbit to another
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6
Q

What is Planck’s Quantum Hypothesis?

A
  • light is made of photons (emit light) - no continuous and colour depend on stability of atom
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7
Q

What is the hydrogen spectrum?

A
  • in a discharge tube, electrons become temp. excited and move further away from nucleus
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8
Q

Difference between long waves and short waves in length?

A

Long = low energy - does not move as far
Short = high energy - moves farther

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9
Q

What is the wave theory of light?

A

Light is a form of electromagnetic radiation
- in wave pattern
- travels at constant speed in vaccum

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10
Q

What did De Brogile propose?

A

Dual wave-particle properties of light may apply to matter
- electrons exist as “matter waves” around nucleus

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11
Q

What is the Wave-Mechanical model/who created it?

A

find the exact position and energy of electron in atom
- SCHRODINGER

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12
Q

What is the uncertainty principal/who created it?

A
  • HEISENBERG
  • it is impossible to know exact location and energy of electron
  • rather the wave-mechanical model is a the probability of where the electron is
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13
Q

What is Aufbau’s principal?

A

Electrons must be added to lowest energy orbital first

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14
Q

What is Hund’s Rule?

A

Due to repulsion, all orbitals acquire 1 electron before getting the second

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15
Q

What is Pauli’s Exclusion Principal?

A

Electrons in same orbital have opposite spin + no 2 electron within an atom can all have same 4 quantum numbers

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16
Q

What are the exceptions of Aufbau’s Principal?

A

d4 and d9 - take from s so it becomes fill or half full (next best thing)

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17
Q

What is the exception of transition metals

A
  • ions
  • take from s for cations before d orbital
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18
Q

What are the implications of Schrodinger’s work?

A
  • Orbitals - 3D cloud around nucleus
  • Diff shape, size, distance from nucleus
  • each orbital holds 2 electrons
  • each energy level has 1+ cloud
    —— ALL FROM QUANTUM #
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19
Q

What is isoelectronic?

A

Meaning having the same # of electrons

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20
Q

Trend in atomic radius

A

–> decrease, down = incrases

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21
Q

What is the trend in ionization energy?

A

IE1 < IE2 < IE3….

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22
Q

What is coordinate covalent bonds/Dative Bonds?

A

when 1 atom donates both of electron that share between 2 atoms - Dative bonds
- a covalent bond (a shared pair of electrons) in which both electrons come from the same atom TO CREATE ANOTHER BOND

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23
Q

What is resonance?

A

when there are multiple ways of writing a lewis structure

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24
Q

Why does resonance occur?

A

electrons are always moving -> causing possibilities

25
Q

What is formal charge

A

charge of the element within the compound

26
Q

What is the lewis theory of bonding

A

noble gases are most stable
- stable octets are formed from transfers or sharing of electrons
- Atoms and ions are stable if they have a noble gas like structure (full octet)
- Electrons are most stable with paired
- Atoms form chemical bond to achieve a stable octet
- Stable octet may be achieved by exchange of electrons between metals and nonmetal atoms
- sharing electrons = covalent bond

27
Q

What is free radical?

A

when atoms have unpaired electrons that are reactive

28
Q

What are the types of bonds?

A
  1. sigma
  2. pi
29
Q

What is the molecular orbital theory?

A

states that atomic orbitals can combine to form molecular orbitals (combination of atomic orbitals to represent the sharing of electrons over 2+ atoms)

30
Q

What is the valence bond theory?

A

A quantum mechanical model of bonding where covalent bond combine 2 electrons to get pair
- Half filled orbitals in one atom can overlap with another half filled to form new bonds (to be stable)
- Overlap of atomic orbitals contain pair of electrons of opposite spin

31
Q

What is the rule of 5 bonds and 6?

A
  • it has to be within or above (higher in energy) of 3p orbitals
32
Q

What are the 4 aggregates?

A

Covalent crystal, ionic crystal, metallic crystals, covalent network

33
Q

What is the theory of atomic spectra?

A

When atoms are excited they emit light of certain wavelengths which correspond to different colors

34
Q

What are properties of covalent network?

A
  • Due to the large molecule of covalent network is strong
  • Electrons in covalent network crystals are held either within atoms or in covalent bonds → electrons are not freely to move
  • insoluble in water
35
Q

Properties of molecular crystals?

A
  • Properties can be explained
    a) Structure
    b) intermolecular force → not strong
  • insoluble in water
36
Q

Properties of metallic?

A
  • Properties of metals result of the bonding between positive nuclei, and loosely held, valence electrons
  • This attraction is not localized or direct between specific atoms
    a) Low ionization cause loosely held electrons
    b) electron mobility (the ability to move freely or be easily moved) BECAUSE THERE ARE EMPTY VALENCE ORBITALS
    c) Electrostatic attraction (sea of positive centers and negative charged electrons) explain strong, non directional bonding
  • INSOLUBLE IN WATER
37
Q

What are ionic crystals?

A
  • Have ionic bonding
  • Has greater force than all intermolecular forces
  • soluble in water
38
Q

How to predict boiling points?

A
  • More polar (hydrogen or dipole dipole)= higher boiling point
  • Greater # of electrons = more london = higher boiling
39
Q

What is hybridization?

A

intermixing of atomic orbitals with the same energy levels to give the same number of a new type of hybrid orbitals

40
Q

What are the type of bonds:

A
  1. 1 = sigma
  2. double = 1 pi and 1 sigma
  3. triple = 2 pi and 1 sigma
41
Q

Explain hydrogen ion:

A
  • the electrons become temporarily excited and thus move to orbits that are farther from the
    nucleus
  • These transitions are only temporary, though,
    so the electrons return to their lowest (or ground)
    states
  • When they do so, they give off energy –> emit a certain light
42
Q

In atomic spectra, why is purple closer together?

A

The electrons shells are unoccupied by electrons = no electron repulsion

43
Q

What is the order in colour for atomic spectra?

A

Red, orange, green, blue, purple

44
Q

What depends on the atom to emit a certain colour?

A
  • How stable/unstable an element is
  • More stable = travel less -> need more energy as already happy and stable
  • Less stable = can travel more, needed energy
45
Q

What are hybrid orbitals -> WHAT CAUSES THE SHAPES?

A

the fact that 2 atoms/orbitals are coming together and thus altering the shape

46
Q

Difference between pi and sigma bonds?

A
  • Sigma bond overlapping of the atomic orbitals of two atoms. -> OVERLAP
  • A pi bond where the electrons are on top and bottom of the axis connecting the nuclei of the joined atoms -> CONNECT TO NUCLEUS SIDEWAYS
47
Q

What is the exceptions of the PT trends?

A
  • when one orbital has 1 electron and other is filled
    • half full is next best thing to filled orbitals
48
Q

How to explain ionization in PT with orbitals?

A
  • Ca and Ba both have 2 electrons in last orbital, BUT Ba has more electrons and more orbital, so that attraction is spread less
49
Q

What do each quantum # implicate?

A

n = energy level
l = orbital
ml = orientation of orbital
ms = spin of electron

50
Q

Why do electrons need opposite spins?

A

They repel each other and want to be as fair from each other as possible

51
Q

what are the delta electronegativity numbers?

A

0-0.5=nonpolar
0/5-1/7=polar
1.7+= ionic

52
Q

How to determine polarity of molecule?

A
  1. find EN
  2. look at shape (asymmetrical/symmetrical from VSEPR) -> from this u can also find intermolecular force
53
Q

REMINDERS:

A
  • WRITE S- AND S+
  • WRITE BRACKETS FOR IONS AN POLYATOMICS IN LEWIS DIAGRAM
  • JUST BECAUSE A SHAPE IS LINEAR -> DOES NOT MEAN IT IS NONPOLAR (THE GUIDE IS USED FOR THE SAME TYPE OF ELEMENT)
54
Q

Is it harder to break an intra or inter force

A

intra -> inside compound

55
Q

Why is graphite an exception to covalent network?

A

Because the pi bonds in unhybridized p orbital -> allowing electrons to move across the structure
structure is like a sandwich but empty in the middle

56
Q

What is the Van Der Waal force?

A

Van der Waals forces include attraction and repulsions between atoms, molecules, and surfaces, as well as other intermolecular forces

57
Q

What is the difference between covalent network and covalent?

A

molecular solid forms due to the action of Van der Waal forces whereas covalent network solid forms due to the action of covalent chemical bonds

58
Q

What is Polarizability?

A

Polarizability is defined as the ease with which the electron cloud of an atom or molecule is distorted