MOD. 2 chapter 2.1 Flashcards
Define a mole
The amount of any substance containing as many particles as there are carbon atoms in exactly 12 g of the carbon 12 isotope
Define avocadros constant
The number of atoms per mole of the carbon 12 isotope
Define molar mass
mass per mole of a substance. The units are g mol ^ -1
Define amount of a substance
The quantity that has moles as its unit… a way of counting atoms
Relative isotopic mass
The mass of an atom of an isotope compared with one twelfth of an atom of carbon 12
Relative atomic mass
Weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon 12
Define molar gas volume-
the volume per mole of a gas. The units of volume are dm3 mol -1. At room temp and preassure the molar volume is approximately 24.0 dm 3 -1
define molecular formula
the number of atoms of each element in a molecule
define empirical formula
the simplest whole number ratio of atoms of each element in a compound
define percentage yield
maximum amount of product you can obtain.
examples of bases
metal oxides, metal carbonates
define oxidation numbers
the number of electrons LOST OR GAINED OR SHARED by an atom in a compound
what oxidation numbers do unconbined elements have
0xidation number 0=== no charge
define what is meant by polyatomic ions
similar compounds but the sum of the oxidation numbers adds up to the charge on the ion
difference between an oxidising agent and a reducing agent
an oxidising agent oxidises something else and reduces itself
a reducing agent, reduces something else and oxidises itself
what happens to the oxidation number when oxidation increases
oxidising number increases eg 2- to 3+ charge
what are oxyanions
negative ions with oxygen
what do the names of oxyanions end in
-ate
name some ions ending in ide
Sulfide (S 2-)
nitride (N 3-)
oxide (O 2-)
who discovered the proton
Rutherford
who discovered the neutron
James Chadwick
Outline Daltons atomic theory
atoms are tiny particles that make up elements.
different elements are made up of different atoms
atoms cannot be divided
Outline JJ Thompsons plum pudding atom theory
JJ discovered that cathode rays have negative charges
could be deflected by both magnet and electric fields
very small mass
Daltons idea that atoms could not be split any further was disapproved.
JJ proposed that negative electrons move around in a sea of positive charge.
atom has no overall charge
Outline Rutherford’s gold leaf experiment and its findings
Directed alpha particles towards a sheet of thin gold foil.
the plum pudding model should’ve had no deflections but his findings were;
Most particles deflected as expected
some deflected at large angles
very few particles actually deflected back to the the source
he then proposed:
electrons orbit the nucleus
positive charge and most of the atoms mass is concentrated in the nucleus.
