Foundations Unit 2 Flashcards
1
Q
What’s an isotope
A
Atom of same element with same number of protons and electrons but different number of neutrons.
They have the same chemical properties because they have the same number of electrons in their outer shell
2
Q
What’s relative atomic mass
A
Mean mass of an atom compared to 1/12th the mass of a carbon12 atom
3
Q
What’s relative isotopic mass
A
Mass of the isotope compared to 1/12th the mass of a carbon 12 atom
4
Q
What’s stoichiometry
A
Molar relationship between the relative quantities of substances taking part in a reaction - like a recipe
5
Q
What’s a molar mass
A
Mass per mole of a substance with units of g mol-1. To calculate we just add all relative atomic mass of each element in compound
6
Q
What does the mass number tell us
A
Number of protons and neutrons in the nucleus
7
Q
What does the atomic number tell us
A
Number of protons in the nucleus
8
Q
What’s relative isotopic mass
A
Mass compared to 1/12th the mass of carbon-12
9
Q
What’s meant by a Bronsted Lowry Acid
A
Proton donor
Ha–> H* + A- reversable
<—
10
Q
What’s a strong bronsted lowry acid
A
Proton donor that completely dissosciates
Ha—-> H*+A-
11
Q
What’s meant by a weak bronsted lowry acid?
A
Proton donor that partially dissociates
Ha—> H* + A-
<—
12
Q
What does the strength of an acid depend on
A
Dissociation of the acid in water.
13
Q
What’s meant by a bronsted lowry base
A
Proton acceptor
OH- + H* –> H²0
14
Q
What’s an alkali
A
Alkali releases OH- ions into a solution
NaOH–> Na+ +OH-
15
Q
What’s meant by a salt and give eg
A
Acid + base or
When the H+ in an acid is replaced by a metal ion or an ammonium
16
Q
Polybasic acids. What’s meant by a monobasic, dibasic, and tribasic acid
A
Monobasic - 1 mole of acid released 1 mole of protons
Dibasic acids- 1 mole of acid releases 2 moles of protons
Tribasic acids - 1 mole of acid releases 3 moles of protons
17
Q
What does acid + metal form
A
Salt + hydrogen
There’s also fizzing and solid dissolves
18
Q
What does acid + metal oxide form
A
Salt + water
Solid dissolves
19
Q
What does acid + metal hydroxide form
A
Salt + water
No visible change
20
Q
What does acid + metal carbonate form
A
Salt + water + carbon dioxide
21
Q
What’s meant by oxidation state
A
Tells us the total number of electrons it has donated or accepted to form an ion or form part of a compound
22
Q
Give the rule for assigning oxidation staes for uncombined elements/ elements which are bonded to identical elements
A
Oxidation state is 0
23
Q
Give the rule for assigning oxidation states to monotonic ions (charged particle consisting of only 1 atom)
A
Oxidation state is gonna be same as their charge
24
Q
Give the rule for assigning oxidation states for molecular ions
A
Sum of all oxidation states= same as oxidation state of molecular ion
25
Give the rule for assigning oxidation states for neutral compounds
Sum of oxidation state is 0
26
State the rule for assigning oxidation states for peroxides metal hydride and fluorine compounds
Oxidisation state of H in metal hydrides 0, In peroxides and Fluronine is combin3d -1
Metal hydrides have more than 1 H Peroxides have 2 9xygens bonded
27
What's the name given to each shell, presented by letter n
Principle quantum number,
28
How can you find out how many electrons are present in a given shel
Using 2n*2 rule
29
State the 4 subshells and how many electrons they can hold
S, p, d, f
2 6 10 14
30
What's an orbital
A region that can hold upto 2 electrons of opposite spins
31
What are the 3 properties of electrons
Spin, mass and charge
32
What is within a shell
Subshells, and within subshells are orbitals
33
What's the name of the shape of an s orbital and draw the shape of it
Spherical shape,
Circle on the graph thing
34
What's the shape of a p orbital and draw the shape of py orbital
Dumb bell shape
Py is straight dumbell, pz is tilted px is laying
P orbital is all 3
35
Whats ionic bonding
Strong electrostatic attraction between oppositely charged ions
36
What's covalent bonding and 2 exceptions to octet rule
Normally happens between non metals. Shared pair of electrons
Boron can hold 6 electrons in outer shell and sulfur can hold 12e
37
What's dative covalent bonding
Shared pair of electrons where both electrons come from same atom.
38
What's metallic bonding
Electrostatic attraction between positively charged ions and delocalised electrons
39
I'd there's 2 electro,s
2 bonded pairs and 0 Lome pairs what's the name and bond angle and diagram
X-X-X 180* linear
40
What is if when there's 3 electrons
3 bonded pairs 0 Lome pairs what's shape, bind and nams
Triagnol planar 120*
X
|
X
/ \
Y. Y
41
What happens when there's 4 electrons
4 bonded 0 Lone, name shape and bond
Tetrahderal 109.5
Y
|
Y《 X \ Y
Y >
42
What happens when there's 4 electrons 3 bonded and one Lone pair
Pyramidal 107*
(xx)
》X
/ \
> Y
43
What happens when there's 4 electrons, 2 bonded 2 Lone.
Non linear. Bond is 104.5
(xx) (xx)
X
/ \
Y. Y
44
4 electrons 4 bonded 2 regions of electro density
Linear shape 180
Y=X=Y
45
What happens when there's 6 electrons bonded. Name shape and bind
Octahedral 90*
Y》Y《Y
|
X
> <
Y. | Y
Y
46
Define what is meant by the term 'Electronegativity'
Ability of an atom to attract electrons in a covalent bond
## Footnote
Electronegativity is a key concept in understanding how atoms interact in chemical bonds.
47
What is the most electronegative element on the periodic table?
Fluorine
## Footnote
Fluorine has an electronegativity value of 3.98 on the Pauling scale.
48
State the trend in estimating electronegativity of elements.
Closer element is towards right and higher, the higher the electronegativity
## Footnote
Electronegativity generally increases across a period and decreases down a group in the periodic table.
49
What do Pauling Values show?
Electronegativity
## Footnote
Pauling values are a scale to quantify the electronegativity of elements, with higher values indicating a stronger ability to attract electrons.
50
What does a larger Pauling value imply?
The larger it is, the larger the electronegativity
## Footnote
This means that elements with larger Pauling values are more effective at attracting electrons in a bond.
51
Define what is meant by a dipole.
Partial positive and negative charge caused by the uneven distribution of electrons
## Footnote
Dipoles are crucial in understanding molecular polarity and intermolecular forces.
52
Why are C-H bonds classed as being non-polar?
Difference in electronegativity is very small
## Footnote
The electronegativity of carbon and hydrogen is similar, resulting in a non-polar bond.
53
What is the overall rule for deciding if a molecule with multiple bonds is polar?
If there's an overall dipole, the molecule is polar.
## Footnote
An overall dipole indicates an uneven distribution of electron density.
54
How can you tell if a molecule is non-polar in terms of symmetry?
If polar bonds are arranged symmetrically, dipoles cancel out, resulting in no overall dipole.
## Footnote
Symmetry in molecular geometry often leads to non-polar characteristics.
55
How can you tell if a molecule is polar in terms of symmetry?
If the dipoles are arranged roughly all in the same direction, the dipoles don't cancel out, and the molecule will have an overall dipole.
## Footnote
This results in a molecule having distinct positive and negative ends.
56
What's a dipole
Partial positive and negative charge caused by uneven distribution of electrons.
57
Why are molecules polar
Difference in electronegativity so dipoles cancel out
58
What are the 3 types of intermolecular forces between molecules
Permanent dipole - dipole interactions
Induced dipole - dipole interactions
Hydrogen bonding (strongest)
59
Describe permanent dipole - dipole forces
(Occur in polar molecules.)
Intermolecular forces that exist because the difference in electronegativities In a polar bond causes weak electrostatic forces of attraction between molecules
60
Describe hydrogen bonding
Occurs in polar molecules that contain (O-H F-H and N-H)
Strongest intermolecular force
61
What are induced dipole - dipole interactions
(All molecules have this)
Caused by movement of electrons within the shells
This causes an instantaneous dipole across the molecule
The instantaneous dipole in one molecule induces a dipole in a neighbouring molecule, which in turn induce a dipole on their neighbouring molecules
The small induced dipoles attract one another causing a weak intermolecular force
62
What happens to a larger atom with induced dipole dipole interactions
Will have stronger induced dipole dipole interactions between atoms / molecules
Which requires more energy to overcome
63
What are the 2 anomalous properties of ice and water
Ice is less dense than water as molecules in ice are held apart by hydrogen bonds
Ice has a relatively high melting point as the hydrogen bonds are relatively strong
64
Why does bromine have a greater boiling point than chlorine
Bromine is larger and has more electrons than chlorine
Bromine has stronger induced dipole diple interactions between molecules
So requires more energy to overcome
65
Describe ionic compounds structure and bonding sbec
Structure - Giant ionic lattice
Bonding- strong electrostatic attraction between oppositely charged ions
Energy -which requires large amounts of energy to overcome
Conductivity - conducts electricity when molten or dissolved as ions are mobile, not when solid as ions are in a fixed position
So high BP and mp
66
Describe metallic compounds structure and bonding sbec,
Structue- giant metallic lattice
Bonding - metallic bonds,electrostatic attraction between positively charged ions and delocalised electrons
Energy - require large amount of energy to overcome
Conductivity - conducts electricity when molten or solid as it contains delocalised electrons which are mobile
Metals are malleable - can be shapes and ductile- can be worn into wore
67
Describe simple covalent compounds
S- simple covalent lattice
B- intermolecular forces between molecules
E- are weak so require little energy to overcome
C - don't conduct electricity as they have no mobile charged particles
68
Describe Diamond structure and bonding
S- Giant covalent lattice
B - lots of strong covalent bonds between carbon atoms.
E- lots energy required to overcome so high BP and MP
C- Can't conduct electricity all outer electrons are held in localised bonds
Insoluble
69
Describe graphite structure and bonding g
S - giant covalent lattice
B- lots of strong covalent bonds between carbon atoms
E - requires lots of energy to overcome so high BP and mp
C - can conduct electricity as it has mobile delocalised electrons
Insoluble
Weak induced dipole - dipole interactions between layers allow layers to slide over each other
Used in pencils and as dry lubricant
70
Describe graphene
1 atom thick making it very light weight but strong at the same time
Delocalised electrons carry a charge quickly as they move above and below the sheet
Uses - high speed electronics aircraft
71
What's meant by the term ionic lattice
Repeating pattern of oppositely charged ions
72
What's the arrangement of a lattice
Repeating pattern
73
Explain why (CH3)2S has a low boiling point and is insoluble in water (3 marks)
Intermolecular forces are involved.
Weak intermolecular forces are broken by a small amount of energy (why its low bp)
Doesn't form hydrogen bonds to water so it's not soluble
74
Statevbond angle of non linear shape and explain
104.5
2 bond pairs and 2 Lone pairs repel
Bonded pairs repel
Lone pairs repel more than bonded pairs
75
What's meant by the term weighted mean mass
Mean mass taking into account the relative abundances of the isotopes
76
What's meant by concordant values
Titres within 0.1 cm of eachother
77
Mass charge and position of protons neutrons and electrons
Proton Mass- 1 charge - +1 position - nucleus
Neutron Mass- 1 charge - 0 - position - nucleus
Electron Mass- 1/2000 charge -1 position- shell
78
Differences between atoms of same elements
Physical properties
Num of neutrons
Mass number
79
Explain why a small proportion of molecules have a relative molecular mass of 20
Molecules contain ²H
80
One of Cl2 has m/z value of 72, has 2 molecular ions
Suggest why and predict the m/z values of the others
Contains chlorine 35 and chlorine 37
70 and 74
(35+35)(37+37)
81
What's meant by the term molecular formula
Num of atoms present of each element in a molecule
82
What's the molecular formula
Number of atoms present of each element in a molecule
83
When doing water of crystallisation, suggest one modification that student could do to reduce the percentage error in the mass of water removed
Use larger mass
84
Describe the relative energies of the 2s orbital and each of the 3 2p orbitals In a nitrogen atom
P orbitals have greater energy than s orbitals.
P orbitalshave equal energy
85
Trigonall planar explain its shape
3 bonding regions
electron pairs repel
86
Pyramidal explain its shape
3 bonding pairs and 1 lone pair
of electrons
pairs of electrons repel
87
whats meant by empirical formula
The simplest whole number ratio of atoms present in a compound
