Elements of life

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• Created by: Gemma
• Created on: 15-05-14 18:23
Atomic number - define
The number of protons in the nucleus of an atom + electrons
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Mass number - define
The number of protons and neutrons in nucleus of an atom
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Isotopes
Atoms of the same element with a different mass number, but the same number of protons + electrons
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The number of particles in a mole of any atom - 6.02x10^23
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Relative isotopic mass
The average mass of isotopes - takes account of their abundances
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Relative atomic mass
The mass of an atom relative to 1/12th of the mass of C12 atom
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Relative formula mass
The sum of all the relative atomic masses of all atoms in a molecule - IONS
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Relative molecular mass
The sum of all the relative atomic masses of all atoms in a molecule- COVALENT
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Molecular formula
The actual number of atoms of each element in a compound
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Empiricle formula
The simplest whole number ratio of atoms of each element in a compound
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How does absorption spectra occur?
Electrons are excited to a higher energy level by absorbing light/energy , emits IR radiation/light which is visible as colored lines on a black background , the energy absorbed corresponds to frequency by E=hv gaps btwn energy levels = unique
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How do you get the energy absorbed/emitted for one mole into molecules?
Divide the energy by Avogadros constant
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What is the definition of half life?
The time taken for half the radioactive nuclei to decay
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What is nuclear fusion?
When lighter atoms join to form a heavier atom in high pressure + high temp
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long enough half life to enable detection, emit gamma to enable detection + minimise ionisation to cells, short half life to prevent damage DNA + ionise cells, small dose - harmful , easy to remove from the body
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Who designed the billiard ball model + what does it look like?
Dalton - solid ball representing the nucleus - atoms are solid and indivisible
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Who designed the plum pudding model + what does it look like?
Thompson - ball representing the nucleus with electrons dotted inside the nucleus - negatively charged electrons surrounding a positive core
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Who designed the Rutherford model
Rutherford - electrons in one shell surrounding the nucleus
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How did the Rutherford model come into existence - experiment?
Geiger + Rutherford - fired alpha particles at a gold nucleus
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What did Rutherford + Geiger find?
99.9% of the atom was empty space due to alpha going through, the nucleus has a positive charge -some rebounded straight back , the nucleus has a high mass- some deflected
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What does the Bohr emission spectrum tell us?
That the electrons are in defined shells using the emission spectrum
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What is the modern model
Electrons are in sub-shells + lobes
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What happens to the reactivity of the group 2 elements as you go down the group?
increases
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What happens to the solubility of hydroxides of the group 2 elements as you go down the group?
increases
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What happens to the solubility of carbonates of the group 2 elements as you go down the group?
decreases
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What happens to the thermal stability of carbonates of the group 2 elements as you go down the group?
increases
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trend of pH as you go down group 2?
increases
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Reaction for the reaction of group 2 metals with water
(equation)
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Reaction for the reaction of group 2 metal oxides with acid
(equation)
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Reaction for the reaction of group 2 hydroxides with acid
(equation)
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How did Mendeleev arrange the periodic table in comparison to the modern one?
He ordered elements in terms of their atomic mass, NOW = atomic mass
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Why did Mendeleev swap iodine + telleurium?
their properties didnt fit with the group they were originally placed in
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Parts of the mass spec?
SAMPLE INLET-gaseous atom,IONISATION AREA - hit with pulse/stream of high energy electrons , which knocks off an electron + ionises it,ACCELERATION AREA-given the same KE 1/2mv2 ,TIME OF FLIGHTspeed @which they move depends on the size,DETECTOR-graph
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What is the base peak?
The most common fragment
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What is the molecular ion peak?
The sample which was placed in- the Mr of the whole molecule
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Other cards in this set

Card 2

Front

Mass number - define

Back

The number of protons and neutrons in nucleus of an atom

Isotopes

Card 5

Front

Relative isotopic mass