F321 - ATOMS, BONDS & GROUPS - DEFINITTIONS

OCR AS CHEMISTRY A
TOPIC F321 DEFINITIONS

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  • Created by: Jordan
  • Created on: 19-03-11 01:06

1. Atoms and Electron Structure

 

Isotopes                                    atoms of an element with different numbers of neutrons and different masses

 

Relative atomic mass                  average mass of an atom relative to 1/12 of the mass of a carbon-12 atom

 

Relative isotopic mass                mass of a particular isotope relative to 1/12 of the mass of a carbon-12 atom

 

Orbital                                      a region that can hold up to 2 electrons with opposite spins

 

1st ionisation energy                   energy change when one mole of electrons is removed from one mole of gaseous atoms

 

Successive ionisation energy       energy change when one mole of electrons is removed from one mole of gaseous positively charged ions

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2. Equations and acids

 

Acid                                          proton donor (H+ donor)

 

Base                                         proton acceptor (H+ acceptor)

 

Salt                                           produced when the H+ of an acid is replaced by another positive ion

 

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3. Redox

 

Oxidation                                   loss of electrons or increase in oxidation number

 

Reduction                                  gain of electrons or decrease in oxidation number

 

Disproportionation                      a reaction in which an element is simultaneously oxidised and reduced

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4. Moles and Equations

 

Amount of substance                  the number of moles of substance that you have

 

Mole                                         unit for amount of substance

 

Avogadro constant, NA                number of particles present in a mole (6.02 x 1023 mol-1)

 

Empirical formula                       simplest whole number ratio of the atoms of each element in a compound

 

Molecular formula                      actual number of atoms of each element in a molecule

 

Concentrated                             containing a large amount of solute per dm3

(say 10 mol dm-3 or more)

 

Dilute                                        containing a small amount of solute per dm3

(say 2 mol dm-3 or less)

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5. Bonding and Structure

 

Ionic bond                                 electrostatic attraction between oppositely charged ions

 

Covalent bond                            a shared pair of electrons

 

Metallic bond                             attraction between positive ions and delocalised electrons

 

Electronegativity                        ability of an atom to attract the electrons in a covalent bond

 

Hydrogen bond                          attraction between a lone pair and a hydrogen atom attached to O, N or F

 

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6. The Periodic Table

 

 

Periodicity                                 patterns repeated across different periods (rows of the Periodic Table)

 

 

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Comments

gabriella PAOLONI

simple and effective

Corrie

these are way too simplified...

Zoe

You should use the glossary in the back of the textbook, it has the actual definitions as they appear on the mark scheme

voices

Does any1 have the mark scheme for f321 jan 2011?

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