Flashcards
2. Atomic Structure | IB Chemistry HL
Cards in this deck (45)
- 1State the sub-atomic particles in the atom. (3)1) proton
2) neutron
3) electron - 2State the relative charge of protons, neutrons, & electrons.protons = +1
neutrons = 0
electrons = -1 - 3—
- 4Explain Rutherford's gold foil experiment, the results, & conclusion. State why this experiment was important.Alpha particles (4He2+ (helium-4 nuclei)) were fired at a very thin sheet of gold.
Results: The majority of the alpha particles passed through. However, some were deflected by the gold foil & few bounced back.
Rutherford proposed that atoms have a +vely charged dense nucleus surrounded by a larger region of empty space containing electrons.
His nuclear model was a paradigm shift. - 5Define 'isotope'Atoms of the same element w/ different number of neutrons.
They have the same atomic no. but different mass no. - 6Compare the chemical & physical properties of isotopes.Same chemical properties but different physical properties.
- 7State what the mass spectrometer is used for.It is used to determine the relative atomic mass of an element from its isotopic composition.
- 8Define 'relative atomic mass (Ar)'The weighted average (according to their % abundances) of the atomic masses of its isotopes compared to 1/12th of the mass of 12C.
- 9State the formula for relative atomic mass from its naturally occurring isotopes. e.g bromine contains 50.2% of 79Br & 49.48% of 81Br. Calculate its Ar.Ar = (average mass of one atom of element ÷ 100)
e.g bromine contains 50.2% of 79Br & 49.48% of 81Br.
Ar = ((50.52 x 79) + (49.48 x 81)) ÷ 100 = 79.99 - 10State & explain the stages of operation in a mass spectrometer.1) Injection: The sample is injected into the vaporization chamber.
2) Vaporization: The vaporization chamber vaporizes solid/liquid samples into a gas that streams into the ionization chamber.
3) Ionization: The gaseous atoms/molecules are bombarded w/ electrons via an electron beam to form unipositive ions.
4) Acceleration: The ions are accelerated in an electric field.
5) Deflection: A magnetic field deflects the lighter ions more than the heavy ions.
6) Detection: Ions w/ different masses are detected by an ion detector, which is connected to a recorder. A mass spectrum is produced.
- 11Identify what the height of the peaks, no. of peaks, & x-axis on the mass spectrum.Height of the peaks: relative abundance of the isotopes.
No. of peaks: no. of isotopes of the element.
x-axis: mass/charge ratio (m/z) of each particle (ion) - 12State what the deflection of an ion in the mass spectrometer depends on. (4)1) the absolute mass of the ion
2) the charge of the ion
3) the strength of the magnetic field
4) the velocity (/speed) of the ion which is controlled by the strength of the electric field. - 13State the relationship b/n the m/z (mass/charge) ratio for an ion & its deflection in the mass spectrometer.The lower the ratio, the greater the deflection.
- 14State the 3 types of radioactivity.1) Alpha radiation: A stream of alpha particles (helium nucleus).
2) Beta radiation: Beta particles are fast-moving electrons that are emitted from unstable nuclei as the result of a neutron being converted into a proton & an electron.
3) Gamma radiation: High-energy electromagnetic radiation produced due to transitions between nuclear energy levels. - 15Describe what occurs in alpha decay, beta decay, & gamma emission.Alpha decay:
- Proton no. ↓ by 2
- Nucleon no. ↓ by 4
Beta decay:
- Daughter nuclide is formed
- Proton no. ↑ by 1
- Nucleon no. stays the same
Gamma emission:
- No particels are emitted
- No change to proton no. of the parent nuclide
- No change to nucleon no. of the parent nuclide - 16State the rule for nuclear equations.The sum of the nucleon & proton numbers must be equal on both sides of the equation.
- 17State what radioactive isotopes are used for. State an example in medicinal chemistry.Used as tracers & followed through a process.
e.g 60Co is used in radiotherapy. - 18State what the line emission spectrum for hydrogen provides evidence for.The existence of electrons in discrete energy levels, which converge at higher energies.
- 19State how emission and absorption spectra are produced.Emission spectra: when photons are emitted from atoms as excited electrons return to a lower energy level.
Absorption spectra: when the electron absorbs energy in the form of a photon, causing it to move up to a higher energy level (an unstable excited state) from a ground state. - 20State the value of the speed of light.3.00 x 10^8 ms^-1
- 21Define 'frequency' State the units for frequency.The no. of cycles a wave goes through every second.
Units: seconds (s^-1) or Hertz (Hz) - 22State the wave equation (relationship b/n speed of light, wavelength, & frequency)c = ν x λ
where:
c = speed of light = 3.00 x 10^8 ms^-1
ν = frequency = s^-1
λ = wavelength = nm - 23State the colours of the continuous spectrum using an acronym.ROYGBIV
Red
Orange
Green
Blue
Indigo
Violet - 24UV-A radiation: 320-380 nm (wavelength) UV-B radiation: 290-320 nm (wavelength) State whether UV-A or UV-B is less dangerous. Explain.UV-A rays are less dangerous than UV-B rays to the skin & eyes.
Bc UV-A rays have a larger wavelength than UV-B rays, which means that it has a lower frequency than UV-B rays. Lower frequencies have less energy and are less harmful. - 25Define 'converge'To get closer together
- 26State what occurs to the energy levels (described by the integer, n) (e.g n=1, n=2, n=3... n=∞) as n increases.The energy levels become closer & finally converge.
- 27Define 'electron transition'The movement of an electron b/n energy levels.
- 28State Planck's equation.ΔE = h x ν = (h x c) / λ
where:
ΔE = energy difference b/n energy levels = J
h = Planck's constant = 6.63 x 10^-34 Js
ν = frequency of light = Hz or s^-1
c = speed of light = 3.00 x 10^8 ms^-1
λ = wavelength = nm - 29State how to convert 1m to nanometers.1m = 10^9 nm
- 30Distinguish b/n a continuous spectrum & line spectrum.A continuous spectrum is a spectrum that consists of all electromagnetic wavelengths across a range of wavelengths.
A line spectrum consists of electromagnetic radiation of specific wavelengths. - 31State the region of the electromagnetic spectrum in which the frequency of photons is emitted when an electron falls from higher energy levels to n=1. State the name given to this series.Ultraviolet region of the EM spectrum.
Lyman series
- 32State the region of the electromagnetic spectrum in which the frequency of photons is emitted when an electron falls from higher energy levels to n=2. State the name given to this series.Visible region
Balmer series
- 33State why an element can be identified from its atomic emission spectrum.Bc every element has its own unique emission (line) spectrum.
- 34Define 'atomic orbital' State how many electrons it can holdA region in an atom where there is a high chance of finding an electron.
Each orbital can hold max. 2 electrons (spin pair) - 35Draw & describe the shape of the s orbital.Spherical in shape
Symmetrical around the nucleus
1 orbital can hold 2 electrons in total.
- 36Draw & describe the shape of the p orbital. State how many p orbitals there are & how many electrons they can hold it total.Dumbell shaped
3 orbitals can hold 6 electrons in total.
- 37Label this orbital State how many d orbitals there are & how many electrons they can hold it total.d-orbital
5 orbitals can hold 10 electrons in total (2 electrons in each orbital)
- 38State how many f orbitals there are & how many electrons they can hold it total.7 orbitals can hold a total of 14 electrons.
- 39State the formula for the max. no. of electrons in each shell.2n^2
where n = the shell (main energy level) no. - 40State why the 4s sub-level is filled before the 3d sub-level.Bc 4s sub-level is of lower energy than the 3d sub-level.
- 41State the Aufbau principle.Aufbau = to build (in German)
In the ground state of an atom/ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. - 42State Hund's ruleEvery orbital in a subshell is singly occupied with one electron (w/ parallel spins) b/f the electrons pair up.
- 43State the Pauli exclusion principleEach orbital can hold a max. of two electrons (w/ opposite spins)
- 44State the two exceptions to patterns in the electronic configurations. State their electron configurations1) Copper: [Ar] 3d^10 4s^0
2) Chromium: [Ar] 3d^5 4s^1 - 45When atoms in the d-block are ionized, from which sub-level are electrons removed first? e.g a 3d-block element4s electrons are removed first.
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- Chemie Flashcards on 2. Atomic Structure | IB Chemistry HL, created by Risa Kunii on 02/08/2019.
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- Risa Kunii · Aug 2019
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- Aug 2, 2019
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