Atomic struture

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  • Created by: Ruby-joy
  • Created on: 12-03-16 12:59
Sub atomic particles
The subatomic particles are protons,neutrons and electrons .Neutrons have a charge of 0 and a mass of 1
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The mass and charge of subatomic particles
Protons have a charge of +1 and a mass of 1 and neutrons have a mass of 1 and a charge of -1.Electrons have a mass of 1/1840 and a charge of -1
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Arrangement of subatomic particle
Protons and neutrons are held toether by strong nuclear charge which is stronger than electrostatic forces. The electrons surround the nucleus.
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Mass number
The mass number is the number of protons and neutrons in an atom.it is given the letter A.It is the top number of a element on a periodic table.
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Atomic number
Atomic number is the number of protons in a atom.
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Isotopes
Atoms with the same number of protons but different number of neutrons.
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Reaction of isotopes
Different isotopes of the same element react similarly because they have the same electron configuration.
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Reaction of isotopes
Isotopes have different masses due to them having different numbers of neutrons.
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Example of istopes
carbon 12,13 and 14
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Relative atomic mass Ar
Average mass of 1 atom /1/12 mass of 1 carbon 12 atom
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Relative molecular mass Mr
Average mass of a molecule / 1/12 the mass of 1 carbon 12 atom
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Mass spectrometer
Determines the mass of separate atoms .
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Steps of a Time Flight mass spectrometer
Vaccum;It needs to be under a vacuum otherwise air particles would ionise and register on the detector
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Ionisation
Sample is dissolved in a polar solvent .A high voltage is applied to sample .The particles lose an electron ( or more) .Forming positive ions with different charges E.g. Ti  Ti+ + e–
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Acceleration
Acceleration Positive ions are accelerated by an electric field .To a constant kinetic energy
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Ion drift
Drift Area The positive ions with smaller m/z values will have the same kinetic energy as those with larger m/z and will move faster. •The heavier particles take longer to move through the drift area. •The ions are distinguished by different flight
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Detection
The ions reach the detector and generate a small current, which is fed to a computer for analysis. The current is produced by electrons transferring from the detector to the positive ions. The size of the current is proportional to the abundance of t
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Relative atomic mass
R.A.M = Σ (isotopic mass x % abundance) 100
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Orbital
An orbital is an area where it is most likely to find an electron
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Orbital
Any orbital can only hold two electrons
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S orbitals
Hold two electrons
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P orbitals
Two electrons but are in a set of three.therefore six electrons
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D orbital
Holds two electrons but comes in a set of five.so there are ten electrons
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Spin
Electrons have the properity of spin.two electrons in the same orbital spin in different directions
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Exceptions to orbital rule
4s orbital always fills up before 3d .It also empties before 3d
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Ionisation energy
Ionisation energy is the energy required to remove 1 mole of electrons from 1 mole of atoms in a gaseous state.
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Example of ionisation
H(g)  H+ (g) + e
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Factors that affect ionisation energies
The attraction of the nucleus (The more protons in the nucleus the greater the attraction)
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Distance
The distance of the electrons from the nucleus (The bigger the atom the further the outer electrons are from the nucleus and the weaker the attraction to the nucleus)
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Sheilding
Shielding of the attraction of the nucleus (An electron in an outer shell is repelled by electrons in complete inner shells, weakening the attraction of the nucleus)
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Why are successive ionisation energies always larger?
The second ionisation energy of an element is always bigger than the first ionisation energy. When the first electron is removed a positive ion is formed. The ion increases the attraction on the remaining electrons and so the energy required to remov
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Periodicity
A repeating pattern across a period is called periodicity.
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Why has Helium the largest first ionisation energy?
Its first electron is in the first shell closest to the nucleus and has no shielding effects from inner shells. He has a bigger first ionisation energy than H as it has one more proton
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Why do first ionisation energies decrease down a group?
As one goes down a group, the outer electrons are found in shells further from the nucleus and are more shielded so the attraction of the nucleus becomes smaller
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Why is there a general increase in first ionisation energy across a period?
Why is there a general increase in first ionisation energy across a period?
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Why has Na a much lower first ionisation energy than Neon?
This is because Na will have its outer electron in a 3s shell further from the nucleus and is more shielded. So Na’s outer electron is easier to remove and has a lower ionisation energy.
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Why is there a small drop from Mg to Al?
Al is starting to fill a 3p sub shell, whereas Mg has its outer electrons in the 3s sub shell. The electrons in the 3p subshell are slightly easier to remove because the 3p electrons are higher in energy and are also slightly shielded by the 3s elect
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Why is there a small drop from P to S?
With sulphur there are 4 electrons in the 3p sub shell and the 4th is starting to doubly fill the first 3p orbital. When the second electron is added to a 3p orbital there is a slight repulsion between the two negatively charged electrons which makes
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Second ionisation energy
Second ionisation is greater than first ionisation energy as it is harder to remove an electron from a positive ion than from a neutral atom • Jumps in ionisation energies occur when going from one energy level (shell) to another. The jump occurs bec
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Trend in group 2
Ionisation energies decreases as atom get bigger more shielding means less attraction.
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Tends in group 3
1st ioisation energy increases bigger nuclear charge but same shielding.
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Group 3
There is a dip from Mg to Al as Mg is losing 3s electron, Al is losing 3p. 3p is higher in energy, easier to remove.
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Group 3
Dip from P to S because P is 3p3, S is 3p4. Mutual repulsion of paired electrons in S make electron easier to remove than in P.
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Atomic radius in group 3
decreases because more nuclear charge but same shieldng.
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Electronegativity
increases because – bigger nuclear charge, same shielding, stronger attraction between nucleus and shared pair of electrons
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Melting point of group 3
sodium,magnesium and aluminium are metallic.Strong attraction between de localised electrons and ions.
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Si
Si has very high melting point. Giant covalent structure has many strong covalent bonds to be broken
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P4,S8,Cl2
P4, S8 and Cl2 have low melting points. These are simple covalent molecules held together by weak Van der Waal’s forces. Van der Waal’s forces increase with molecular mass so S8 has highest melting point, then P4 then Cl2.
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Ar
Ar has simple atomic structure. Fewest electrons, weakest Van der Waal’s forces between atoms
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Other cards in this set

Card 2

Front

Protons have a charge of +1 and a mass of 1 and neutrons have a mass of 1 and a charge of -1.Electrons have a mass of 1/1840 and a charge of -1

Back

The mass and charge of subatomic particles

Card 3

Front

Protons and neutrons are held toether by strong nuclear charge which is stronger than electrostatic forces. The electrons surround the nucleus.

Back

Preview of the back of card 3

Card 4

Front

The mass number is the number of protons and neutrons in an atom.it is given the letter A.It is the top number of a element on a periodic table.

Back

Preview of the back of card 4

Card 5

Front

Atomic number is the number of protons in a atom.

Back

Preview of the back of card 5
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