Chemistry Definitions
Made specifically for AS level Chemistry, OCR
2.0 / 5 based on 2 ratings
- Created by: Molly
- Created on: 01-11-12 12:38
Atomic (proton) Number
Number of protons in the nucleus of an atom
1 of 37
Mass (Nucleon) Number
Number of particles (protons and neutrons) in an atom
2 of 37
Isotopes
Atoms of the same element with different numbers of neutrons
3 of 37
Ion
Positively or negatively charged atom or (covelently bonded) group of atoms (a molecular ions)
4 of 37
Relative Isotopic mass
The mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12
5 of 37
Relative atomic mass
the weighted average mass of an atom of an element compared with 1/12 of the mass of the atom carbon-12
6 of 37
Relative molecular mass
The weighted average mass of a molecule compared with 1/12 of the mass of an atom of C-12
7 of 37
Relative formular mass
the weighted mean mass of a formula unit compared with 1/12 of the mass of an atom of C-12
8 of 37
Amount of substance
the quantity whose unit is the mole. Chemists use 'amount of substance' as a means of counting atoms
9 of 37
Avagadro Constant
the number of atoms per mole of the C-12 isotope (6.02x10^23)
10 of 37
Mole
the amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the C-12 isotope
11 of 37
Molar Mass (M)
the mass per mole of a substance. Units are g mol^-1
12 of 37
Empirical Formula
the simplest whole-number ratio of atoms of each element present in a compound
13 of 37
Molecule
Small group of atoms held together by a covalent bond
14 of 37
Molecular formula
the actual number of atoms of each element in a molecule
15 of 37
Molar Volume
the volume per mole of a gas. The units of molar volume are dm^3 mol^-1. At room temp and oressure the molar volume is approx. 24.0 dm^3mol^-1
16 of 37
Concentration of a solution
amount of solute, in mol, dissolved per dm^3 of solution
17 of 37
Standard Solution
solution of known concentration. Standard solutions are normally used in titrations to determine unknown information about the other substance
18 of 37
Oxidation Number
a measure of the number of electrons that an atom uses to bond with atoms of another element. Oxidation numbers are derived from a set of rules.
19 of 37
Oxidation
loss of electrons or increase of oxidation number
20 of 37
Reduction
gain of electrons or decrease of oxidation number
21 of 37
Reducing agent
reagent that reduces (adds electron to) another species
22 of 37
Oxidising agent
a reagent that oxidises (takes electrons from) another species
23 of 37
First Ionisation Energy
the energy required to remove one electron from the outer shell of each atom in 1 mol of gaseous atoms. Forming 1 mol of gaseous 1+ ions.
24 of 37
Electron Shielding
the repulsion between electrons in different inner shells. Shielding reduces the net attractive force from the positive nucleus on the outer shell electrons
25 of 37
Successive ionisation energies
measure of energy required to remove each electron in turn
26 of 37
Shell
a group of orbitals with the same principal quantum number.
27 of 37
Principal Quantum number,n
a number representing the relative overall energy of each orbital, which increases with distance from the nucleus. The orbitals with the same n-value are reffered to as electron shells or energy levels.
28 of 37
Atomic orbital
a region within an atom that can hold up to two electrons with opposite spins
29 of 37
Sub Shell
a group of the same type of atomic orbitals (s,p,d or f) within a shell
30 of 37
Electron Configuration
arrangement of electrons within an atom
31 of 37
Compound
substance formed from two or more chemically bonded elements in a fixed ratio, usually shown by a chemical formula
32 of 37
Giant Ionic Lattice
a three-dimensional structure of oppositely charged ions held together by strong ionic bonds
33 of 37
Group
verticle column in the PT. Elements in the group have similar chemical properties and their atoms have the same number of outer-shell electrons
34 of 37
Covalent bond
bond formed by a shared pair of electrins
35 of 37
Lone pair
an outer-shell pair of electrons that is not involved in chemical bonding
36 of 37
Dative Covalent (coordinate bond)
A shared pair of atoms that has been provided for by one of the bonding atoms only
37 of 37
Other cards in this set
Card 2
Front
Number of particles (protons and neutrons) in an atom
Back
Mass (Nucleon) Number
Card 3
Front
Atoms of the same element with different numbers of neutrons
Back
Card 4
Front
Positively or negatively charged atom or (covelently bonded) group of atoms (a molecular ions)
Back
Card 5
Front
The mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12
Back
Related discussions on The Student Room
Similar Chemistry resources:
0.0 / 5
0.0 / 5
0.0 / 5
4.0 / 5 based on 1 rating
4.5 / 5 based on 10 ratings
4.0 / 5 based on 3 ratings
5.0 / 5 based on 12 ratings
5.0 / 5 based on 2 ratings
4.0 / 5 based on 1 rating
2.0 / 5 based on 16 ratings
Comments
No comments have yet been made