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4 Periodic Table
Term | Definition |
---|---|
Element | a substance that cannot be split into simpler substance by chemical means and consists of only one type of atom |
Robert Boyle | Gave the first definition of an element |
Humphry Davy | Discovered Potassium by passing an electric current through a compound of potassium |
Discoverer of Sodium, Calcium, Barium, Strontium and Magnesium | Humphry Davy |
Dobereiner's triads | A group of three elements with similar chemical properties in which the atomic weight of the middle element is approximately equal to the average of the other two. |
Newlands' Octaves | Arrangement of elements in which the first and the eight element counting from a particular element, have similar properties. |
Mendeleev's Periodic Law | When elements are arranged in order of increasing atomic mass the properties of the elements repeat periodically. |
Group | elements with similar properties in the same vertical column |
Moseley | using X-rays, he determined the number of protons in the nucleus of an atom. |
Atomic Number | The number of protons in the nucleus of an atom |
Modern Periodic law | Elements are arranged in order of increasing atomic number, the properties of the elements recur periodically |
Mass number | The sum of the number of protons plus the number of neutrons in the nucleus of an atom of that element. |
Isotopes | Atoms of the same element with the same atomic number but different mass numbers due to the different number of neutrons in the nucleus. |
Frances Aston | Built the mass spectrometer to measure the mass of atoms |
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 exactly 12 units. |
Mass Spectrometer Process | Vaporisation, Ionisation, Acceleration, Separation, Detection |
Vaporisation | A small amount of gas or liquid is injected into the instrument at the sample inlet, as there is a very good vacuum inside the instrument, Liquids quickly turn to gases |
Ionisation | Electron gun fires high-energy electrons at the atoms or molecules of the sample of gas, electrons are knocked off these particles and positive ions are formed |
Electron Gun | Heated filament that gives off electrons |
Acceleration | Positive ions pass between a series of negatively charged plates |
Detection | By changing the strenght of the magnetic field, the mass spectrometer brings ions of different masses to focus on the detector. |
Mass spectrometer | Used to identify unknown compounds, drug detection, forensics & space composition of atmospheres and surfaces of planets |
Electron configuration | Shows the arrangement of electrons in an atom of an element. |
S Sublevel | can hold 2 electrons and has only one orbital |
P sublevel | can hold 6 electrons and has 3 orbitals |
P orbital | Dumb-bell shaped, are located on the x, y & z axes |
An Orbital | a region in space where there is a high probability of finding an electron, can hold only 2 electrons. |
Na 11 = | 1s2,2s2,2p6,3s1 |
Cu29 = | 1s2,2s2,2p6,3s2, 3p6, 4s1, 3d10 |
Cr24 = | 1s2,2s2,2p6,3s2, 3p6, 4s1, 3d5 |
Co27 = | 1s2,2s2,2p6,3s2, 3p6, 4s2, 3d7 |
N7 = | 1s2,2s2,2p3 |
Mg+ = | 1s2,2s2,2p6,3s1 |