A student studying GCSE science is puzzled by data A chlorine atom has more protons in it's nucleus compared to a sodium atom
which indicate that a sodium atom is larger than a Both have 3 shells of electrons
chlorine atom and that a sodium ion is smaller than a Electrons more strongly attracted by chlorine nucleus
chloride ion. How should an A-level Chemistry student so size smaller than Na
explain this apparently conflicting information. (6) An electron shell is lost when a sodium atom turns into a sodium ion
Inner electrons more strongly attracted so ion smaller than atom
An electron is added to the outer shell when a chloride ion is formed
Greater repulsion between shells so size of chloride ion bigger than chlorine
atom
What is the relative mass of an electron?(1) 1/1840
Explain why isotopes have similar chemical Identical electron configuration
properties(2) Chemical properties depend on electrons
Define the term relative atomic mass.(1) (average mass of an atom/ 1/12 mass of 1 atom of carbon 12
,Explain, in detail, how the relative atomic mass of this Mass spectrum gives m/z value
element can be calculated from data obtained from Mass spectrum gives relative abundance
the mass spectrum of 3 different isotopes(5) Multiply m/z by relative abundance for each isotope
Sum these values
Divide by the sum of relative abundances
Use your knowledge of structure and bonding to I2 is molecular
explain why the melting point of iodine is low (113.5 °C) HI is molecular
and why that of hydrogen iodide is very low (-50.8 °C). IM forces hold the molecules together
(6) There are weak IM forces in both molecules hence why melting points are low
I2 bigger molecule so has more electrons
Therefore stronger van der Waals between molecules in I2 that need more
energy to break causing the melting point to be higher.
HI also shows permanent dipole-dipole attraction between molecules but
these forces are less than the vdW forces in iodine.
Chloroethane reacts with potassium hydroxide in the KOH = base
presence of propan-1-ol to form ethene. propan-1-ol = solvent
State the role of potassium hydroxide and the role of
propan-1-ol in the reaction.(2)
, Write an ionic equation, with state symbols, to show Ca(s) + 2H20(l) > Ca2+(aq) + 2OH-(aq) + H2
the reaction of calcium with an excess of water.(1)
Outline how the TOF mass spectrometer is able to Positive ions accelerated by electric field
separate two species to give two peaks.(4) To a constant kinetic energy
The lighter ions have the same kinetic energy and move faster
Therefore the lighter ions arrive first
State and explain the general trend in first ionisation General increase
energy across Period 3.(4) Increasing nuclear charge
Similar shielding
Stronger attraction from the nucleus for outer electrons.
State the element in Period 3 that has the highest Silicon
melting point. Giant covalent structure
Explain your answer.(4) Many covalent bonds
Need a lot of energy to overcome
Explain why nickel is ductile (can be stretched into Layers can slide over eachother
wires).(1)
which indicate that a sodium atom is larger than a Both have 3 shells of electrons
chlorine atom and that a sodium ion is smaller than a Electrons more strongly attracted by chlorine nucleus
chloride ion. How should an A-level Chemistry student so size smaller than Na
explain this apparently conflicting information. (6) An electron shell is lost when a sodium atom turns into a sodium ion
Inner electrons more strongly attracted so ion smaller than atom
An electron is added to the outer shell when a chloride ion is formed
Greater repulsion between shells so size of chloride ion bigger than chlorine
atom
What is the relative mass of an electron?(1) 1/1840
Explain why isotopes have similar chemical Identical electron configuration
properties(2) Chemical properties depend on electrons
Define the term relative atomic mass.(1) (average mass of an atom/ 1/12 mass of 1 atom of carbon 12
,Explain, in detail, how the relative atomic mass of this Mass spectrum gives m/z value
element can be calculated from data obtained from Mass spectrum gives relative abundance
the mass spectrum of 3 different isotopes(5) Multiply m/z by relative abundance for each isotope
Sum these values
Divide by the sum of relative abundances
Use your knowledge of structure and bonding to I2 is molecular
explain why the melting point of iodine is low (113.5 °C) HI is molecular
and why that of hydrogen iodide is very low (-50.8 °C). IM forces hold the molecules together
(6) There are weak IM forces in both molecules hence why melting points are low
I2 bigger molecule so has more electrons
Therefore stronger van der Waals between molecules in I2 that need more
energy to break causing the melting point to be higher.
HI also shows permanent dipole-dipole attraction between molecules but
these forces are less than the vdW forces in iodine.
Chloroethane reacts with potassium hydroxide in the KOH = base
presence of propan-1-ol to form ethene. propan-1-ol = solvent
State the role of potassium hydroxide and the role of
propan-1-ol in the reaction.(2)
, Write an ionic equation, with state symbols, to show Ca(s) + 2H20(l) > Ca2+(aq) + 2OH-(aq) + H2
the reaction of calcium with an excess of water.(1)
Outline how the TOF mass spectrometer is able to Positive ions accelerated by electric field
separate two species to give two peaks.(4) To a constant kinetic energy
The lighter ions have the same kinetic energy and move faster
Therefore the lighter ions arrive first
State and explain the general trend in first ionisation General increase
energy across Period 3.(4) Increasing nuclear charge
Similar shielding
Stronger attraction from the nucleus for outer electrons.
State the element in Period 3 that has the highest Silicon
melting point. Giant covalent structure
Explain your answer.(4) Many covalent bonds
Need a lot of energy to overcome
Explain why nickel is ductile (can be stretched into Layers can slide over eachother
wires).(1)
