Unit one AQA, with a little of unit 2.

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  • Created by: Kat.I
  • Created on: 15-12-13 16:23
Define isotope.
Atoms with the same number of protons but a different number of neutrons.
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Define atomic number.
The number of protons in the nucleus of an atom.
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Define mass number
The sum of the protons and neutrons in the nucleus of an atom.
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Define relative atomic mass.
The mass of an atom relative to that of the carbon 12 isotope having the value of 12.
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Define empirical formula.
The simplest whole number ratio of the elements in a compound.
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Define molecular formula.
The exact number of atoms of each element in the formula of a compound.
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What is a functional group?
A functional group is an atom or group of atoms which when present in different molecules causes them to have simular chemical properties.
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When going across a period from left to right does electro-negativity increase or decrease ?
Increase.
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When going down a group does electro-negativity increase or decrease ?
Decrease.
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In larger molecules are permanent dipole forces or van der waals forces stronger ?
van der waals.
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Define first ionisation energy.
The first ionisation energy of an element is defined as the enthalpy change for the removal of one mole of electrons from one mole of atoms of the element in the gas phase
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Define molecular formula.
The molecular formula gives the actual number of atoms of each element present in a molecule.
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What is a structural isomer?
structural isomers are compounds with the same molecular formula but different structures.
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What is the general trend of first ionisation energies across period 3?
Increasing.
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Whats the 4 stages in a mass spectrometer?
1) ionisation 2) acceleration 3) deflection 4) detection
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Explain why ions formed in a mass spectrometer have a positive charge.
Because they have lost one (or more) electrons hence have a negative charge.
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What causes the ions to accelerate through the mass spectrometer?
They are attracted by a positively charged plate.
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In a mass spectrometer what forms ions into beams?
The ions pass through a series of holes or slits.
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In a mass spectrometer what bends the ions into a curved path?
A magnetic field at right angles to their direction of motion.
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What is Hess's law
The enthalpy change when one mole of a compound is formed in its standard state from its elements in their standard states.
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Define standard enthalpy of combustion.
The energy required to remove one mole of electrons from one mole of gaseous atoms to for one mole of gaseous positive ions.
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How many electrons does the first, second and third shell hold?
1st - 2 electrons 2nd - 8 electrons 3rd - 18 electrons
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Define ionic bond
Oppositely charged ions held together in a crystal lattice by electrostatic attraction.
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Define covalent bond.
A shared pair of electrons one electron being supplied by each atom either side of the bond.
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Define electro-negativity.
The ability of an atom to attract the pair of electrons in a covalent bond to itself.
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Define polar bond.
A covalent bond where the shared pair of electrons is displaced to one end.
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Define bond enthalpy.
The energy required to break one mole of gaseous bonds to form gaseous atoms.
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Other cards in this set

Card 2

Front

Define atomic number.

Back

The number of protons in the nucleus of an atom.

Card 3

Front

Define mass number

Back

Preview of the front of card 3

Card 4

Front

Define relative atomic mass.

Back

Preview of the front of card 4

Card 5

Front

Define empirical formula.

Back

Preview of the front of card 5
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