Karteikarten
Inorganic - Atomic structure
Karten in diesem Stapel (18)
- 1Describe changes to the atomic theory over time until the present day.1661 - Boyle determined that there were elements that could not be made simpler, elements, as we now know them.
1803 - Dalton suggested all elements were made up of atoms, and these could not be broken down.
1896 - Becquerel discovered radioactivity, showing particles could come from inside the atom.
JJ Thompson discovered the electron and suggested the plum pudding model.
1911 - Rutherford discovered that the mass of the atom was concentrated at the nucleus, and the electrons orbited this nucleus. - 2What are the three particles that make up an atom?Neutron, proton, electron
- 3What are the relative masses and charges of each sub-atomic particle?
- 4What is the force holding protons and neutrons together?The strong nuclear force - this is stronger than the electrostatic forces between protons and electrons, so overcomes repulsion between protons in the nucleus.
- 5Define atomic number and mass numberAtomic number - number of protons
Mass number - number of nucleons - 6What is an isotope?An atom with the same atomic number but a different mass number, as it may have more or less neutrons in the nucleus. It has the same number of protons and electrons, with the same configuration, so is chemically similar to the normal atom.
- 7What are the 3 (4) orbitals that electrons can be found in?s,p,d,f
- 8What is a mass spectrometer?A piece of equipment that can be used to find the relative atomic masses of atoms in a sample.
- 9Define relative atomic mass (Mr)The mass of an atom relative to carbon measured on a scale where the mass of carbon-12 is exactly 12.
- 10What is the type of spectrometer used to identify Mr of substances?Time of flight spectrometer - TOF
- 11What are the steps by which the relative mass of an atom is measured in a TOF spectrometer?The equipment must be kept in a vacuum, preventing ions colliding with molecules in the air. The sample must be ionised, either by electrospray (sample passed through a narrow needle with a high voltage, causing the sample to lose electrons, forming positive ions) or electron impact (electrons are knocked off by other electrons). The ions are accelerated to a constant kinetic energy by a negative plate. The ions drift down the tube, with lighter ions travelling faster than heavier ions. When ions reach the detector, they gain electrons from it, causing a current to flow, allowing the ions to be detected. The time of flight corresponds to the mass of the ions. This data is passed to a computer for analysis.
- 12Why might there be several peaks on a mass spectrum?The isotopes may combine in different ways (a molecule of Cl2 could be made from 2 Cl-35 atoms, 2 Cl-37 atoms, or one of each. The peaks will be of the ratio that the isotopes are in abundance. There will also be peaks of ionised molecules ( in chlorine there will be 3, one for 35/35, one for 35/37, and one for 37/37). Finally, the sample may have fragmented.
- 13Draw the shapes of the s and p orbitalss - sphere around nucleus
p - hourglass shape with centre on nucleus - 14What is the property of electrons in a configuration?Electron spin - they spin in opposite directions in each orbital - represented by arrows.
- 15Write the full electronic configuration of sodium.1s2 2s2 2p6 3s1
- 16Write the full electronic configuration of copper.1s2 2s2 2p6 3s2 3p6 4s1 3d10
Electrons are lost from 4s before 3d, important for ions and certain transition metals - Cr and Cu - 17What is ionisation energy?The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form a mole of gaseous 1+ ions.
- 18What are the trends in ionisation energy?First electron removed requires less energy than the 2nd or 3rd as you are removing from a less charged particle. - Successive ionisation energies.
The closer the electron to the nucleus, the harder it is to remove - higher electrostatic force and less shielding.
Energy increases across a period as nuclear charge increases. Small drops between s and p orbitals as p is at a higher energy level, so electron is more easily removed. Small drop between 3p3 and 3p4 and electron repulsion makes 3p4 easier to remove as it is paired to another electron.
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- A level Chemistry Karteikarten am Inorganic - Atomic structure, erstellt von Adam Parkes am 20/12/2020.
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