1.1 - Basic ideas about atoms, second half

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  • Created by: Danielle
  • Created on: 05-12-13 08:49
What are successive ionisation energies
a measure of the energy needed to remove each electron in turn until all the electrons are removed from an atom.
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Name the two reasons successive ionisatoin energies always increase
- as each electron is removed there is less electron to electron repulsion and so will be drawn slightly closer to the nucleus. - as the distance between the electron and the nucleus decreases the nuclear attraction increases
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Name a reason for a large increase in successive ionisation energies
An electron has been removed from a new shell closer to the nucleus
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What is the electromagnetic spectrum?
The range of all possible frequencies of electromagnetic radiation
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The ____ the wavelength, the ____ the frequency, the ____ greater the energy.
Lower, Higher, Higher or Higher, Lower, Lower
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Explain how the absorption spectra works
When white light is shone through gaseous atoms, photons of a certain energy may be absorbed by an atom causing an electron to move from a lower to a higher energy level. The light of a frequency will correspon to the energy of the photon.
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Explain how the emission spectra works
When atoms are given energy by heating or electrical field electrons go from low to high energy level. When the source of energy is removed the return to lower energy level releasing a quantum of energy.
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What does the absorbtion spectra look like?
Dark lines against a bright background
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What does the emission spectra look like?
Coloured lines on a black background
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What is electronic transition?
When an electron moves from one energy level to another
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What energy level do the electrons return to in the balmer series?
Energy level n=2
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What energy level do the electrons return to in the lyman series?
Energy level n=1
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What is the convergence limit?
When the spectral lines become so close together they have a continuous band of radiation and separate lines cannot be distinguished
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In the hydrogen spectrum, as the frequencies increase the lines get ___ ___ because the energy difference between the shells ___.
closer together - decreases
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How can the ionisation energy be calculated in the hydrogen spectra?
ΔE=hf
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What is ΔE?
The energy of the emitted radiation which is the difference between the two energy levels
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What is the convergent frequency/ ionisatoin energy drawn?
from n = 1 to n = infinity
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*11 The first four ionisatoin energies (kJ) for an element are; 738, 1451, 7733, 10541. State and explain to which group in the periodic table the element belongs.
Group 2 because there is a large jump in energy between the 2nd and 3rd ionisation energy, therefore the third electron has been removed from a new shell
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*12 Two lines in the emission spectrum of atomic hydrogen have the following frequencies 460 THz and 690 THz. State and explain which one has the higher (a) energy (b) frequency
(a) Line with 690 THz has the higher energy since E is indirectly proportional to f (b) Line with 460 THz has the higher wavelength since f is inversely proportional to 1/wavelegnth
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*13 State briefly the difference between absorption and emission spectra
In AS, energy is absorbed from light causing electrons to move from a lower to a higher e level. Seen as dark lines against a bright background. In ES, energy is emitted as electrons fall back from a high to low EL. Seen as colored line on black
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*14 In the atomic spectrum of hydrogen, why do the spectral lines get closer at the high frequency end of the Balmer series?
As frequency increases the energy levels in an atom get closer, therefore the energy difference between levels decreases, so the lines get closer
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*10 Write an equation to represent the second ionisation energy of magnesium.
Mg+ (g) -> Mg2+ (g) + e-
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Other cards in this set

Card 2

Front

Name the two reasons successive ionisatoin energies always increase

Back

- as each electron is removed there is less electron to electron repulsion and so will be drawn slightly closer to the nucleus. - as the distance between the electron and the nucleus decreases the nuclear attraction increases

Card 3

Front

Name a reason for a large increase in successive ionisation energies

Back

Preview of the front of card 3

Card 4

Front

What is the electromagnetic spectrum?

Back

Preview of the front of card 4

Card 5

Front

The ____ the wavelength, the ____ the frequency, the ____ greater the energy.

Back

Preview of the front of card 5
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