Electron Configuration and Experimental skills Flashcards
What is a systematic error
A recurring error which is inherent in the apparatus or experimental method used. Repeating the procedure and averaging results doesn’t eliminate random errors
3 ways to reduce systematic error
Re-calibrate instrument, change apparatus or procedure, use new standards
What are random errors
Chance variations between successive Measurements.
Random errors are indicated by ‘…’ In the measure values
Scatter
How to reduce the effect of random errors
Taking the average of repeated measurements or drawing a ‘line of best fit’ through the plotted points on a graph
The precision of a series of measurements is indicated by the degree of uniformity - the more ‘…’ The less precise
Scatter
A measurement is ‘…’ to the extent that random errors have been minimised
Precise
A measurement is ‘…’ To the extent that systematic errors have been minimised
Accurate
What is the formula for K, L, M and N
2n^2
How many electrons can K, L, M and N
2, 8, 18, 32
What can an orbital be visualised as
A blurry cloud of negative charge: the charge is most dense where the probability of finding the electron is the largest
How many orbitals and electrons does the S subshell contain
1 orbital - 2 electrons
How many orbitals and electrons does the subshell p contain
3 orbitals - 6 electrons
How many orbitals and electrons does the subshell d hold
Orbitals 5, Electrons 10
How many orbitals and electrons does the subshell f hold
Orbitals 7, Electrons 14
What is Hund’s Rule
When electrons occupy orbitals of equal energy, one electron enters each orbital until all orbitals contain one electron
What two elements do not follow the usual pattern
Chromium, Copper
What are the last two subshells of chromium
3d^5, 4s^1
What are the last two subshells of copper
3d^10 4s^1
Which electrons should be deleted first and second to create ion subshell notation
4s and 3D
How to figure out the group and period using subshell configuration
Period = number of occupied electron shells Group = number of electrons in the valence shell (Roman numerals)
Define Energy sequence of orbitals
Electrons enter orbitals of lowest energy first
define Pauli Exclusion Principal
Orbitals can only accommodate a maximum of 2 electrons, and these must have opposite spins
Metals ‘…’ Electrons in chemical reactions
Lose
Non-metals “…” Or “…” Electrons in chemical reactions
Gain or share
Metalloids ‘…’ Or ‘…’ In chemical reactions
Lose or share
What can atoms of periods 3 and 4 do with elements from group V to VII
Share all their outer shell electrons
Where do extra electrons go when expanding the octet
3d shell
In group 1 elements what is the charge of a monatomic ion and the oxidation state of elements
1+ & +1
In group II elements what is the charge of a monatomic ion and the oxidation state of elements
2+ & +2
In group III elements what is the charge of a monatomic ion and the oxidation state of elements
3+ & +3
In group IV elements what is the charge of a monatomic ion and the oxidation state of elements
2+ or 4+ and +4, +2 or -4
In group V elements what is the charge of a monatomic ion and the oxidation state of elements
3- & +5, +3, or -3
In group VI elements what is the charge of a monatomic ion and the oxidation state of elements
2- & +6, +4, +2 or -2
In group VII elements what is the charge of a monatomic ion and the oxidation state of elements
1- & +7, +5, +3, +1 or -1
What is electronegativity
Ability of an atom to attract electrons to itself
An ‘…’ Substance can donate or accept protons
Amphiprotic
An ‘…’ Substance can react with an acid or a base
Amphoteric
What are acidic oxides oxides of
Non-metals
What do acidic oxides react with hydroxide ions to form
Oxyanions
What is an ionic bond
Between metal and non-metal atoms
What is a metallic bond between
Metal atoms
What are covalent bonds between
Non-metals
What are the bonds between atoms called
Primary bonds
What are bonds between molecules
Secondary or intermolecular
3 types of secondary bonds
Dispersion forces, dipole-dipole and hydrogen Bonding
7 properties of ionic compounds
- Usually crystalline solids 2. High melting and boiling points 3. Dissociate in water 4. Solids won’t conduct electricity 5. Conduct electricity as a molten or in aqueous solution 6. Hard 7. Brittle
Are polar bonds shared equally
No
Two properties a molecule must have to be polar
Polar bonds, asymmetrical charge distribution
Like dissolves in ?
Like
What does the strength of dispersion forces depend on
The number of electrons, the more electrons the stronger the molecule
How do dipole dipole reactions work
The positive end of one molecule is attracted to the negative end of another neighbouring molecule in polar molecules only
What does hydrogen bonding form between
Hydrogen attached to nitrogen, oxygen or fluorine in one molecule and nitrogen, oxygen or fluorine in another molecule.
How does hydrogen bonding work
When N, O and F are covalently bonded to hydrogen molecules leaving them exposed, this then strongly attracts the electronegative nitrogen, oxygen or fluorine in the neighbouring dipoles
Would Nitrogen or CO2 have a higher boiling point
CO2
Which would have a higher boiling point HF or HCL
HF
Which has a higher boiling point SO2 and SF6
SO2
Which would have a higher boiling point
NH3 and PF3
Covalent molecules substance tend to have relatively ‘…’ Melting and boiling points
Low
What is a continuous covalent lattice, give three examples
A giant structure in which no individual molecules exist, Silicon Dioxide/ Quartz (SiO2), Silicon Carbide (SiC) and Diamond (C)
6 properties of covalent network lattices
Very hard, brittle, high melting and boiling points, non conductors (No free electrons), Insoluble
What is decomposition
A chemical reaction in which a compound breaks down into simpler compounds or elements.
What is aerobic respiration
The process in which foodstuffs are fully oxidised with the release of chemical energy. Process requires a ready supply of molecular oxygen
Anaerobic respiration
Process by which foodstuffs are partially oxidised, with the release of chemical energy, in the absence of molecular oxygen.
Alcoholic fermentation is a type of ‘…’ Respiration which one of the end products is ‘…’
Anaerobic, ethanol
Aerobic products of Carbon, Hydrogen, Sulfur, Nitrogen, Phosphorus
Carbon Dioxide, Water, Sulfates, Nitrates, Phosphates
Anaerobic products of Carbon, Hydrogen, Sulfur, Nitrogen, Phosphorus
Methane, Water, Hydrogen Sulphide, Ammonia, Phosphine
Two key processes of the carbon and oxygen cycle and their equations
Photosynthesis: 6CO2 + 6H2O -(Sunlight & Chlorophyll)-> C6H12O6 + 6O2
Respiration: C6H12O6 + 6O2 –> 6CO2 + 6H2O + Energy
What is nitrogen fixation
The conversion of atmospheric nitrogen into soluble nitrogen compounds such as nitrates and ammonium salts.
What is the nitrogen cycle
The continuous chemical interchange between nitrogen in the atmosphere and the biosphere
What is found in the nodules on the roots of legume plants
Nitrogen fixing bacteria which contain an enzyme that catalyses the conversion of atmospheric nitrogen into ammonia or ammonium compounds
Other than microbes, what initiates nitrogen fixation and how do they do this
Lightening discharge and forest fires, high energy produced are sufficient to break the triple bond in the N2 molecule
Two formulas related to natural nitrogen fixation through microbes, fires, lightening etc
N2 + O2 –> 2NO
2NO + O2 –> 2NO2
Formula for forming nitrate ions which are deposited in the soil when it rains
2NO2 + H2O –> H(+) + NO3(-) + HNO2
Causes of artificial nitrogen fixation
Combustion of fuels in the internal combustion engine and industrial furnaces produce the high temperatures needed
What is the reaction the haber process uses high temperatures in artificial nitrogen fixation to bring about
N2 + 3H2 –> 2NH3
What can ammonia be used as after the Haber process
Plant fertiliser
What is denitrification
The process by which diatomic nitrogen is returned to the atmosphere
Reaction between rock phosphate and sulfuric acid which produces superphosphate
Ca3(PO4)2 + 2H2SO4 –> CaSO4 + Ca(H2PO4)2
What is water pollution brought on by excess nutrients
eutrophication
Photochemical smog is a form of …
Lower atmosphere air pollution
Formula for general rain
CO2 + H2O -> H2CO3
Oxides of Sulfur two equations
Compounds of Sulfur + O2 -> SO2
2SO2 + O2 -> 2SO3
How does acid rain effect foliage
Causes damage that affects water loss from leaves, disrupts photosynthesis,
How does acid rain effect soil
Leaches essential ions, can mobilise potentially toxic ions
How does acid rain effect bacteria, include equation (aluminium)
Free aluminium ions can also damage bacteria that plants need
Al2O3 + 6H+ -> 2Al3+ + 3H2O-
How does acid rain effect the fish population
Fish can suffer from excessive loss of sodium from the gills, free aluminium ions can restrict extraction of oxygen,
How does acid rain effect human health
Toxic metal ions can be transported in solutions of drinking water eg dams and wells
How does acid rain impact the built environment
Buildings made of limestone, marble and sandstone are washed away due to how they react with acid rain
Two formulas for acid rain with calcium carbonate (Limestone and Marble)
CaCO3 + H2SO4 -> CaSO4 + CO2 + H2O
CaCO3 + HNO3 -> Ca(NO3)2 + CO2 + H2O
Formula for pH
-Log[H3O+] [Concentration]
Formula for concentration
10^pH OR -pH = log[H+]
What is the waste product of the burning of fossil fuels
Carbon dioxide
What role does carbon dioxide play in the earth
Regulates the temperatures on Earth
How does carbon dioxide regulate the earths temperature and what is this process known as
Allows solar radiation, blocks heat radiated from the earths surface from escaping, acts like a one way blanket,
greenhouse effect
What are the green house gases
Carbon dioxide, water vapour, methane, nitrous oxide and halocarbons
What are the two primary pollutants of photochemical smog
Nitric Oxide and Hydrocarbons
Equation of nitrous oxide and how is it created
N2 + O2 -> 2NO, formed within the combustion chamber of motor vehicle engines
Equation for Nitrogen Dioxide and how is it formed
2NO + O2 -> 2NO2, nitric ochre is slowly oxidised to nitrogen dioxide in the atmosphere, nitrogen dioxide is yellowish brown gas
Two equations for the production of Ozone
NO2 + UV -> NO + O
O + O2 -> O3
Formula for when nitrogen dioxide is reformed from nitric oxide through the destruction of ozone
NO + O3 -> NO2 + O2
3 equations involving Carbon monoxide, hydrocarbons and nitric oxide as a result of a catalytic converter
CO + O2 -> 2CO2
C8H18 + 25O2 -> 16CO2 + 18H2O
2NO + 2CO -> N2 + 2CO2
Why does ammonium Sulfate provide nitrogen in a suitable form for use by plants
As its soluble and dissociates in water, ammonium ions are absorbed in aqueous solution through the roots
Equation for the reaction of ammonium ion with water to form an acidic solution
NH4^+ + H2O ->
If soluble in water what do acidic oxides react with water to form
Oxyacids
Sulfur dioxide reaction with hydroxide ions and reaction with water
SO2 + 2OH^- -> SO3^2- + H2O
SO2 + H2O -> H2SO3 (sulfurous acid)
Basic oxides are oxides of …
Metals
Basic oxides react with acids or hydrogen ions to form
Metal cations and water molecules
If soluble in water what do basic oxides form
Metal cations and hydroxide ions
Sodium oxide reaction with hydrogen ions and water
Na2O + 2H+ -> 2Na+ + H2O
Na2O + H2O -> 2Na+ + 2OH-
