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33 Cards in this Set
- Front
- Back
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What are cathode rays |
Streams of negatively charged particles called electrons that travel in straight lines from the cathode to the anode , are deflected by electric and magnetic fields, and have sufficient energy to move a small object like a paddle wheel |
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What is an energy level |
The fixed energy that an electron in an atom may have |
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What is an orbital |
A region in space within which there is a high probability of finding an electron |
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What is the ground state of an atom |
One in which the electrons occupy the lowest availabke energy levels |
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What is the excited state of an atom |
One in which the electrons occupy higher energy levels than those available in the ground state |
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What is the Heisenberg uncertainty principle |
States that it is impossible to measure at the same time both the velocity and the position of an electron |
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What is a sublevel |
A subdivision of a main energy level and consists of one or more orbital of the same energy |
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What is an element |
A substance that cannot be split into simpler substances by chemical means |
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What is the atomic number of an atom |
The number of protons in the nucleus of that atom |
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What is the mass number of an element |
The sum of the number of protons and neutrons in the nucleus of an atom of that element |
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What are isotopes |
Atoms of the same element which have different mass numbers due to different numbers of neutrons in the nucleus |
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What is the relative atomic mass |
The average of the mass numbers of the isotopes of the element as they occur naturally taking their abundances into account and expressed on a scale in which the atoms of the carbon-12 isotope have a mass of 12 units |
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What is the principle of mass spectrometry |
Charged particles moving in a magnetic field are deflected to different extents according to their masses and are thus separated according to these masses |
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What is hunds rule of maximum multiplicity |
States that when 2 or more orbital of equal energy are available the electrons occupy them singly before filling them in pairs |
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What is the aufbau principle |
When building up the electron configuration of an atom in its ground state the electrons occupy the lowest available energy level |
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What is the pauli exclusion principle |
States that no more than 2 electrons may occupy an orbital and they must have opposite spin |
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What is Daltons atomic theory |
-all matter is made up of minute particles called atoms -all atoms are indivisible |
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What was William crookes discovery |
Discovered cathode rays Investigated what happens when an electric current is passed through a glass vacuum. The glass of the tube was seen to flourese indicating it was being hit with radiation |
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What did jj Thompson do |
Discovered the electron Proposed the plum pudding model of the electron Suggested the formula e/m |
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What did Robert milikan do |
He discovered the size of the share on the electron in the oil drop experiment |
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What did Ernest Rutherford do |
He discovered the nucleus and protons by shooting positively charged alpha particles at gold foil |
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What did James Chadwick do |
Discovered the neutron by shooting alpha particles at bereleyum |
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What colour do these elements turn when energised : Sodium Lithium Pottasium Barium Strontium Copper |
Yellow Crimson Lilac Green Red Blue/green |
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How did bohr explain the emission spectrum of hydrogen |
E2-E1=hf When an atom in its ground state is energised a specific amount of energy is absorbed and the atom is said to be excited. Excited atoms are unstable and soon fall back to a lower energy level releasing the excess energy as a photon of light |
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Name the one visible and 2 invisible series of light |
Invisible: lyman and pashen Visible: balmer |
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What are 3 limitations of the bohr theory |
It could only properly explain the emission spectra of atoms with one electron He didn't take into account the wave nature of the electron He couldn't explain the splitting of lines on the emission spectra thus he did not take onto account the existence of sublevels |
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What does the atomic absorption spectra look like and what principles does it work on |
It looks like a dark line against a coloured background the opposite of the emission spectra. It works on the principle that atoms in their ground state absorb light of a particular wavelength and that the amount of light absorbed is directly proportional to the concentration of the element |
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Name the sublevels |
1s 2s 2p 3s 3p 4s 3d 4p |
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What are doboereiners triads |
A group of 3 elements with similar chemical properties in which the relative atomic mass of the middle element is approximately equal to the average of the other 2 |
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What is newlands law of octaves |
Arrangements of elements in which the first and 8th element counting from a particular element have similar chemical properties |
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How was mendeleevs periodic table assembled |
He arranged them in order of increasing atomic mass so that the properties of the elements recurred periodically |
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Who invented the modern periodic table and how is it arranged |
Henry morseley When elements are arranged in order of increasing atomic number the properties of the element recur periodically |
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3 uses of the mass spectrometer |
To identify unknown drugs To identify the presence of isotopes To measure the relative abundancies of isotopes |
