exam review unit 1 Flashcards

(65 cards)

1
Q

What holds molecules together?

A

Intramolecular and Intermolecular forces.

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2
Q

What are Intermolecular forces

A

Much weaker forces between for molecules or atoms.

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3
Q

what are Intramolecular forces

A

Much stronger forces within a molecule, compound, or polyatomic ion

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4
Q

Can ionic compounds contain intermolecular forces and why

A

No, ionic bonds hold all the ions in the lattice together

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5
Q

What polarity does London dispersion forces have

A

polar and non polar

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6
Q

What polarity is Dipole-Dipole

A

polar molecules

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7
Q

What polarity does hydrogen bonds have

A

dipole-dipole forces containing H so polar

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8
Q

What are London dispersion forces

A

WEAKEST (#3) caused by temporary imbalance of electrons. Similar to dipole-dipole forces. Stronger LDF can increase melting point.

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9
Q

What are Dipole-Dipole forces

A

intermolecular force of attraction between S+ end of a molecule and a S- of another molecule. 2nd strongest.

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10
Q

what are temporary dipole

A

when electrons are constantly revolving, electrons can be denser at one side than the other, then quickly going back to normal.

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11
Q

what is an induced dipole

A

a temporary dipole disturbs a neutral atom to be a temporary dipole. The partial positive side makes the atom be attached to it using its new partial negative side.

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12
Q

what elements do hydrogen bonds happen along with

A

N, O, F (Ammonia, water, hydrogen fluoride)

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13
Q

What is a hydrogen bond

A

(STRONGEST #1) dipole dipole force between hydrogen and a highly electronegative molecule. (NOF)

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14
Q

What do intermolecular forces help do

A

Determine physical properties. State, melting/boiling point, surface tension)

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15
Q

As intermolecular forces increase…

A

physical properties increase (melting/boiling point and surface tension). A solid has a stronger intermolecular force than a liquid, and a liquid has a stronger force than gas. But never strong as covalent.

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16
Q

What is the most polar molecule on earth

A

water

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17
Q

What is denser water or ice

A

Water is denser than ice, which is why ice floats (very unusual). As it freezes, hydrogen bonds arrange into a crystal structure, making more space between molecules. therefore less dense.

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18
Q

Why do lakes and oceans effect climate so much.

A

because water can hold heat without heating up itself as much. It has a high heat capacity.

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19
Q

What is the surface tension of water like?

A

It is strong due to hydrogen bonds. Water strongly holds each other and resists to be broken apart (doing a bellyflop in water hurts). Gives the smallest surface area.

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20
Q

What did Philosophers do to contribute to atomic theory

A

Democritus said that matter can be divided into atomos.
Aristotle said that matter was made by either water, fire, earth, air

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21
Q

What did Alchemists do to contribute to atomic theory

A

specialists that turned metals into gold. Some of these processes are still used today.

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22
Q

What did John dalton do?

A

Made the billard ball model. Big round coloured spheres. Atoms are identical but different to other elements and can make molecules.

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23
Q

What did JJ Thompson do.

A

Founded the electron. Made the plum pudding model (Rasin bun, blueberry muffin, fat bitch)

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24
Q

What did Rutherford do.

A

Did the gold foil experiment and discovered that the nucleus is positively charged and surrounded by electrons. There is a shit ton of empty space that’s also positive.

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25
What did Chadwick do
founded neutrons. Found out they had the same mass as protons.
26
What did Bohr do
found out that energized atoms release specific light colours (Pink Floyd album cover). Also found out that electrons orbit in energy levels.
27
What did Erwin Schrödinger do
Made the quantum mechanical model (electron cloud model).
28
What is the modern atomic theory
1. All matter is made up of atoms that are mode of subatomic particles 2. An element cannot turn into another element chemically 3. Atoms of one element share same properties (Avg mass, size etc) 4. Atoms can form compounds
29
What does standard notation look like
mass number on top, element in the middle, atomic number at the bottom.
30
What are differences in Bohr and Rutherfords diagrams
Bohr: has defined energy levels Rutherford: electrons orbit in undefined paths, mostly in empty space. Both have small dense positively charged nucleus.
31
What is special about the Quantum model
Bohrs diagram wasn't as specific with its electron path as the quantum model is. Quantum can guess where an electron is most likely, not exactly. Denser the 3d location is, the most likely there will be more electrons.
32
What is an isotope
Same element but different electrons (C-12 AND C-14)
33
What is a radioistope
unstable isotopes that decay and emit radiation. It is used for medical treatment such as chemo.
34
What is a mass spectometer
A device to test atomic mass by measuring how ions behave in magnetic fields. It analzyizes unknown compounds and molecular stutter. It can also identify different isotopes.
35
What is the formula for average atomic mass
(%1 x mass1) + (%2 x mass2)
36
What is the atomic radius
distance from nucleus to valence (pms)
37
What are diatomic radius
radius between two nucleus in diatomic molecules
38
Which way does the trend follow on the table for atomic radius and why is this the pattern.
Down towards the left (Fr being the largest). Each energy Level is further away from the nucleus. Shielding effect Effective nuclear charge
39
What is Ionic radius
distance of the centre of an ion to the valence electrons. Cations are smaller and Anions are larger.
40
What is ionization energy
amount of energy needed to remove an electron kJ/mol
41
Which way does the trend follow on the table for ionization energy and why is this the pattern.
up right (F being the most) because less electrons means more effective nuclear charge, meaning its harder to take. Also, closer to Nobel gases means closer to a stable octet.
42
What is Electron Affinity
The amount of energy needed to add an election (kJ/mol)
43
Which way does the trend follow on the table for electron affinity and why is this the pattern.
up right. This is because less energy levels means less shielding. Atomic radius decreases so there is a stronger attraction force between nucleus and valence electrons.
44
What is the shielding effect
Inner electrons block electrons from the pull form the positive nucleus.
45
What is the effective nuclear charge
More protons attract more electrons, therefore closer together.
46
How to determine reactivity on the periodic table
valence electrons are responsible for chemical bonding. Metals are highly reactive and loses electrons, non metals are not very reactive and gains electrons. Nobel gases don't do either as they are stable.
47
What is isoelectronic
Same number of electrons but different number of protons (Ne is isogenic with F-)
48
What is electronegativity
The ability to attract bonding electrons. It is the small numbers on an element that determines the deltaEN.
49
What is the scale for non polar bonds
0-0.5
50
What is the scale for polar covalent bonds
0.5-1.7
51
What is the scale for ionic bonds
1.7 above
52
What are the characteristics of Ionic compounds
- solid at room temp - Cations and anions form crystal lattice - High melting/boiling points due to strong electrostatic forces - Electric when dissolved in water and molten liquids
53
How do ionic compounds turn electric when dissolved in water
When dissolved, cations and anions are attacked by water molecules, creating electrolytes.
54
What is the smallest repeating unit in a compound called (ionic)
formula unit
55
What are electrostatics
a force that holds ions together
56
What is a polar bond
unequally shared partial charges (Cl is more electronegative than hydrogen)
57
What is a polar molecule
an asymmetrical shape that causes a dipole movement
58
What was S- and S+ mean
S- Partial negative: more electronegative S+ Partial postitive: Less electronegative
59
What are the characteristics of molecular compouds
- Can be in any state or form - Cannot conduct electricity in water, or finds difficulty to - Very controlled - Like dissolves like (polar dissolves in polar, non polar dissolves in non polar) - Low melting and boiling point Negative pole attached to a positive pole
60
What does a linear shape look like
O=C=O
61
what does a trigonal planar shape look like
F | B / \ F F
62
What does a tetrahedral shape look like
H | C / | \ H H H
63
what does a Trigonal Pyramidal shape look like
.. N / | \ H H H
64
what does a bent shape look like
: O : / \ H H
65
what does a stronger London dispersion force do to the melting point
increase melting point.