Flashcards
Atomic structure
Flashcards do conjunto (42)
- 1Relative atomic massThe average mass of an atom relative to 1/12th of the mass of a carbon-12 atom
- 2Atomic number, ZNumber of protons in the nucleus of the atom
(remember it's Z by ZAtomic) - 3Mass number, AThe number of protons and neutrons in the nucleus of an atom
- 4A negative ion hasgained electrons
- 5A positive ion haslost electrons
- 6Oxidation isloss of electrons
- 7Reduction isgain of electrons
- 8An isotope isan atom with the same number of protons but different number of neutrons
- 9Relative isotopic massThe mass of an isotope of an element compared to carbon-12
- 10Equation for calculating relative isotopic masssigma (m/z x abundance)
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total abundance or 100( if in %) - 11Relative molecular massAverage mass of a molecule relative to 1/12th the mass of a carbon-12 atom
- 12Give the 5 stages of mass spectrometryVaporisation, Ionisation, Acceleration, Deflection, Detection
- 13VaporisationSample is turned into a gas using an electrical heater
- 14IonisationThe gas particles are bombarded with high-energy electrons to knock off the outer electron and create positive ions
- 15AccelerationThe positive ions are accelerated by an electric field
- 16DeflectionAn electromagnet creates a magnetic field which alters the path of the ions, depending on their m/z ratios
The lighter the ion, the greater the deflection - 17DetectionDifferent ions with different m/z ratios hit the detector plate as the electromagnet's strength is gradually increased. These create a current which produces a mass spectrum
- 18The peak in a mass spectra showsthe isotope which is the most abundant in the sample
- 19The x-axis on a mass spectra isthe m/z (since the charge or z is normally +1, can assume the m/z =RIM)
- 20Why is there sometimes a small peak at m/z 10-11?During ionisation, sometimes two electrons are knocked off, creating positive 2+ ions with half the m/z ratio. These are lighter and deflected more. Appear as a small peak as they are not abundant.
- 21The further an electron from the nucleus,the higher its energy and the smaller its attraction to the nucleus
- 22What are the different sub-shells in the energy levelss,p,d,f
- 23How many electrons can each orbital hold2
- 24How many electrons can each sub shell holds - 2
p - 6
d - 10
f - 14 - 254s fills before 3d becauseit is of slightly lower energy
- 26Why is chromium an exceptionends in 3d5 4s1 - the 3d half fills before filling the 4s to reduce electron repulsion (Hunds Rule )
- 27Copper is an exception because it fills310 completely before 4s as it takes less energy, creates less repulsion
- 28When transition metals form ions,they lose their 4s electron before their 3d
- 29First ionisation energyThe energy required to remove the outer electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions.
- 30Give the equations for the first, second and third ionisation energies of Oxygen0(g) --> 0+(g) + e-
0+ (g) --> 02+(g) + e-
02+ --> 03+(g) + e- - 31An increase in nuclear charge increases the IE becausethere are a greater number of protons in the nucleus therefore there is a greater attraction to the electrons. This makes it harder to remove the outer electron.
- 32An increased distance from the nucleus decreases the IE becausethe electrons are on average further away so the attraction to the nucleus is reduced, making them easier to remove.
- 33An increase in shielding decreases the IE becausethe outer electrons subsequently feel less attraction towards the nuclear charge
- 34Shielding isthe lessening of the pull of electrons by the nucleus caused by the inner shells of electrons
- 35Second Ionisation energy isthe energy required to remove the outer electron from one mole of gaseous 1+ ions to form one mole of gaseous 2+ ions.
- 36Second IE>First IE becausethere is a greater attraction between the positive ion and its electrons (because now there are more protons = higher nuclear charge)
- 37A spin pair (only group 6) decreases the IE becausethe electron is easier to remove due to its repulsion
- 38IE decreases down group two because (2)there is a large increase in shielding which outweighs the increase in nuclear charge (which creates a greater attraction between the nucleus and the electrons)
- 39Jumps in successive IE's are caused bythe next electron being removed from the inner shells which are more and more strongly attracted to the nuclear charge, so take more energy to remove
- 40IE increases across a period because (3)The proton number increases therefore the nuclear charge increases meaning the electrons are more strongly attracted to the nucleus, making them harder to remove. They are also generally at the same energy level (no shielding/distance effect)
- 41The IE of group 3>group 2 becausethe outer electron enters the p orbital, meaning there is an increase in shielding which outweighs the increase in nuclear charge
- 42IE for group 6the new electron is FORCED TO MAKE AN ELECTRON PAIR so repulsion occurs, making it easier to remove the electron. This outweighs the increase in nuclear charge
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- A level Chemistry (Unit 1) FlashCards sobre Atomic structure, criado por Bethany Goh em 21-05-2015.
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- Bethany Goh
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