Chemistry Unit 1 definitions

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  • Created by: ava.scott
  • Created on: 13-04-14 12:46
Relative Atomic Mass (Ar)
The weighted average mass of an atom compared to one-twelfth of the mass of an atom of carbon-12.
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Relative isotopic mass
The weighted average mass of an isoptope compared to one-twelfth of the mass of a carbon-12 atom.
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Relative Molecular Mass (Mr)
The weighted average mass of a molecule compared to one-twelfth of the mass of a carbon-12 atom.
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Relative formula mass (
The weighted average mass of a formula unit compared to one-twelfth of the mass of a carbon-12 atom.
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Empirical Formula
The simplest whole number ratio of atoms of each element in a molecule
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Molecular Formula
The actual number of each atom of an element in a molecule.
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Atomic number
The number of protons in the nucleus of an atom.
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Mass Number
The number of protons and neutrons in the nucleus of an atom.
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Isotopes
Different versions of an element with varying atomic mass/ number of neutrons.
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Acid
A H+ donator in aqueous solution.
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Base
Accepts H+ ions from an acid
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Alkali
A OH- donator in aqueous solution
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Oxidation
The loss of electrons from a molecule/atom, resulting in positive charge.
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Reduction
The gain of electrons in a molecule/atom, resulting in negative charge.
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Disproportionation
The oxidation and reduction of the same element within one redox reaction.
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1st Ionisation energy
The energy needed to remove 1 mole of electrons from 1 mole of atoms in their gaseous state, to produce 1 mole of +1 ions.
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2nd Ionisation energy
The energy needed to remove 1 mole of electrons from 1 mole of +1 ions in their gaseous state to produce 1 mole of +2 ions.
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nth ionisation energy
The energy require to remove 1 mol of electrons from 1 mole of (n-1) ions in their gaseous state to form 1 mole of n+ ions.
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ionic bond
where a metal donates its electrons to a non-metal, forming two oppositely charged ions.
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Covalent bond
Where two non-metals share a pair of electrons to complete their outer shells
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Dative Covalent Bond
when one atom donates both electrons to the shared electron pair
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Electron pair repulsion theory
Electron pairs repel eachother and the number and type of electron pairs surrounding the central atom in a molecule determines its molecular shape.
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Electronegativity
A measure of the attraction a atom has for the bonded pair of electrons across a covalent bond.
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Polar Bond
Where the more electronegative atoms pulls the electrons to it, resulting in a negative charge at that end, and a positive charge at the other e.g. HCl
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Polar Molecule
A molecule in which electron density is not equally distributed resulting in regions with negative and positive charge e.g. H2O, NH3
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Metallic bonding
The electrostatic attraction between protons and delocalised electrons.
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Other cards in this set

Card 2

Front

The weighted average mass of an isoptope compared to one-twelfth of the mass of a carbon-12 atom.

Back

Relative isotopic mass

Card 3

Front

The weighted average mass of a molecule compared to one-twelfth of the mass of a carbon-12 atom.

Back

Preview of the back of card 3

Card 4

Front

The weighted average mass of a formula unit compared to one-twelfth of the mass of a carbon-12 atom.

Back

Preview of the back of card 4

Card 5

Front

The simplest whole number ratio of atoms of each element in a molecule

Back

Preview of the back of card 5
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