(i) The atom consists of extremely denser region at the center called nucleus which have
positive charged particles.
(ii) The negative particles (electron(s)) of atoms revolve around the nucleus in a path
called orbit.
(iii) The large area of atom is empty space.
SHORT COMINGS OF RUTHERFORD ATOMIC MODEL.
Rutherford atomic model accounted that electron revolve around the nucleus in the path called orbit. This is an imagination because no any scientist proved the occurrence but discovered that when charged particle revolve around the opposite charge reach a point when they collapse due
to the attraction force that occurs between the nuclear and electron(s) hence electron capture. But this proved the truth of Rutherford because no any atom discovered to collapse.
BOHR’S ATOMIC MODEL
√The electrons revolve around the nucleus in a path called orbit which have certain energy.
√The electron when revolve in stationery state does not radiate energy.
√The electrons emit or absorb energy when shifting from one energy level to another.
√The electronic motions are those which its angular momentum is integral multiple of where n = 1, 2, 3...
Short coming of Bohr's Atomic Model
•Bohr’s accounted that electrons revolve in a single plane. But it was later discovered that movement of electrons is not restricted in only on plane.
•The Bohr’s atomic model did not explain spectral lines of multi-electrons atom but accounted only spectral lines of uni-electron hydrogen atom.
•The Bohr’s model did not account for electrons which were found in a chemical bond.
•Bohr viewed an electron as being placed at a certain distance from the nucleus. However, it was proved by Weaver Heisenberg’s Uncertainty Principle:–It is impossible at any
movement to predict both the exact position and velocity of an electron in an atom.
MASS SPECTROMETER
Is an instrument which is used to determine the relative atomic mass of an element.
Significance of mass spectrometer.
Determination of the relative molecular mass of a compound and
formula of a compound. In a spectrographic plate.
Mass spectrograph is a plate of mass spectrometers which detect and record the relative atomic mass of an element.
The spectrographic plate is a detector or recorder.
The diagram of mass spectrometer with its part
NB: Can't see the image? Don't worry click on it for clear view!
Figure 7
Working mechanism:
Vaporization.
The instrument is evacuated in order to prevent the interference of air.
The solid sample must be heated until it forms gaseous atoms and vaporized before it’s introduced into the mass spectrometer.
Ionization.
The vaporized sample of element is introduced in the ionization chamber. This region has electric filament which emits fast moving electrons.
These electrons collide with atom
of an element as a result, the atom split which leave only nucleus of positive charge.
The nucleus left is where mass of atom is concentrated.
Acceleration.
The ion particles formed in the ionization chamber are accelerated by two plates of negative charges toward the magnetic field. These two plates are connected to negative potential which accelerate ions as a beam of light toward the magnetic field.
Deflection.
The beam of ion is deflected in the magnetic field. The extent of deflection depends on the mass to charge ratio m/e.
The light particles are deflected more than the heavy particles. The deflected ions strike on the detector.
The ions of the same mass to charge ratios strike on the same spot.
Detection.
As the ions strike the detector in the collector that converts the intensity of the ions into electric signals, is then
amplified by the amplifier into large electric current.
Recording.
The current is used to operate a pen that moves on a paper tracing the peak of the isotope.
The ion is recorded in terms of atomic mass and relative abundance.
As they fall on the photographic plate they produce a mass spectrum that consists of a series of lines at
different point.
The mass of ions is detected on the photographic plate.
Relative abundance is the percentage of an isotopic atom in the element.
The ions particles when strike
the detector produce mass spectrum. The mass spectrum is indeed recorded as a peak.
Mass spectrum sample;
NB: Can't see the image? Don't worry click on it for clear view!
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positive charged particles.
(ii) The negative particles (electron(s)) of atoms revolve around the nucleus in a path
called orbit.
(iii) The large area of atom is empty space.
SHORT COMINGS OF RUTHERFORD ATOMIC MODEL.
Rutherford atomic model accounted that electron revolve around the nucleus in the path called orbit. This is an imagination because no any scientist proved the occurrence but discovered that when charged particle revolve around the opposite charge reach a point when they collapse due
to the attraction force that occurs between the nuclear and electron(s) hence electron capture. But this proved the truth of Rutherford because no any atom discovered to collapse.
BOHR’S ATOMIC MODEL
√The electrons revolve around the nucleus in a path called orbit which have certain energy.
√The electron when revolve in stationery state does not radiate energy.
√The electrons emit or absorb energy when shifting from one energy level to another.
√The electronic motions are those which its angular momentum is integral multiple of where n = 1, 2, 3...
Short coming of Bohr's Atomic Model
•Bohr’s accounted that electrons revolve in a single plane. But it was later discovered that movement of electrons is not restricted in only on plane.
•The Bohr’s atomic model did not explain spectral lines of multi-electrons atom but accounted only spectral lines of uni-electron hydrogen atom.
•The Bohr’s model did not account for electrons which were found in a chemical bond.
•Bohr viewed an electron as being placed at a certain distance from the nucleus. However, it was proved by Weaver Heisenberg’s Uncertainty Principle:–It is impossible at any
movement to predict both the exact position and velocity of an electron in an atom.
MASS SPECTROMETER
Is an instrument which is used to determine the relative atomic mass of an element.
Significance of mass spectrometer.
Determination of the relative molecular mass of a compound and
formula of a compound. In a spectrographic plate.
Mass spectrograph is a plate of mass spectrometers which detect and record the relative atomic mass of an element.
The spectrographic plate is a detector or recorder.
The diagram of mass spectrometer with its part
NB: Can't see the image? Don't worry click on it for clear view!
Working mechanism:
Vaporization.
The instrument is evacuated in order to prevent the interference of air.
The solid sample must be heated until it forms gaseous atoms and vaporized before it’s introduced into the mass spectrometer.
Ionization.
The vaporized sample of element is introduced in the ionization chamber. This region has electric filament which emits fast moving electrons.
These electrons collide with atom
of an element as a result, the atom split which leave only nucleus of positive charge.
The nucleus left is where mass of atom is concentrated.
Acceleration.
The ion particles formed in the ionization chamber are accelerated by two plates of negative charges toward the magnetic field. These two plates are connected to negative potential which accelerate ions as a beam of light toward the magnetic field.
Deflection.
The beam of ion is deflected in the magnetic field. The extent of deflection depends on the mass to charge ratio m/e.
The light particles are deflected more than the heavy particles. The deflected ions strike on the detector.
The ions of the same mass to charge ratios strike on the same spot.
Detection.
As the ions strike the detector in the collector that converts the intensity of the ions into electric signals, is then
amplified by the amplifier into large electric current.
Recording.
The current is used to operate a pen that moves on a paper tracing the peak of the isotope.
The ion is recorded in terms of atomic mass and relative abundance.
As they fall on the photographic plate they produce a mass spectrum that consists of a series of lines at
different point.
The mass of ions is detected on the photographic plate.
Relative abundance is the percentage of an isotopic atom in the element.
The ions particles when strike
the detector produce mass spectrum. The mass spectrum is indeed recorded as a peak.
Mass spectrum sample;
NB: Can't see the image? Don't worry click on it for clear view!
Back/Next
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