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Chapter C1 - Atomic Structure - Coggle Diagram
Chapter C1 - Atomic Structure
C1.2 Chemical equations
Chemical reactions show the reactants (the substances you start with) and the products (the new substances made) in a reaction.
No new atoms are created to destroyed in a chemical reaction: total mass of reactants=the total mass of products
There is the same number of each type of atom on each side of a balanced symbol equation
You can include state symbols to five extra information in balanced symbol equations: These are (s) for solids, (l) for liquids, (g) for gases, and (aq) for aqueous solutions
C1.4 Fractional distillation and paper chromotography
What is crude oil?
A mixture of hydrocarbons with different chain lengths
What process is used to separate
crude oil?
Fractional Distilation
What is done to the crude oil first?
It is heated at high temperatures
What temperature is the bottom of the
column?
Hotter
What is the temperature of the top of
the column?
Cooler
What happens to the liquids when they
cool?
Condense
What is a fraction?
A group of hydrocarbons with similar
boiling points
Name 3 examples of uses of crude oil?
Petrol- for fuel for cars
Kerosene- For aircraft fuel
Bitumen- for road surfacing
Fractional distillation
Fractional distillation is an effective way of separating miscible liquids, using a fractionating column. This occurs because of the different boiling points of the liquids in the mixture.
STEPS FOR FRACTIONAL DISTILLATION OF CRUDE OIL
The crude oil is heated and evaporates
The vapours move up the fractionating column.
As the gases move up the fractionating column they cool down.
The further up the column, the cooler it becomes.
Each fraction condenses at a different temperature.
So it is collected at a different point.
Each fraction contains hydrocarbons with a similar number of carbon atoms.
The refinery gases have very low boiling points and do not condense and pass out of the top of the fractionating column.
Bitumen has a very high melting point and does not evaporate when the crude oil mixture is heated.
As the gases move up the fractionating column they cool down.
Key Words:
Miscible
Liquids that dissolve each other and mix completely
Condenser
Apparatus that cools a gas down and turns into a liquid
Simple distillation
Technique used to separate two liquids with different boiling points
Fractionating column - apparatus for separating many liquids with similar boiling points
C1.7 Ions, atoms, and isotopes
The atoms of an element contain equal numbers of protons and electrons and so have no overall charge
Atomic number or proton number is the bottom number, so in this case '6'. This tells us carbon has 6 protons and 6 electrons
The atoms of any element have an equal number of protons and electrons
The top number is the mass number, therefore it is '12'. This tells us the total number of protons & neutrons in the nucleus.
protons + neutrons = mass number To work out the number of neutrons you need to: Neutrons = Mass number – atomic number
Isotopes are two or more forms of the same element that contain equal numbers of protons and electrons but different numbers of neutrons. They have different mass numbers.
Atoms (even different isotopes) have no overall charge because they have equal numbers of protons and electrons. Therefore the charge cancels out.
An ion is a charged atom. An atom becomes an ion when it loses or gains electrons.
C1.1 Atoms
A group of 2 or more atoms chemically
joined together is a
molecule
H20 - WATER
A
compound
is a substance made of two or more types of atom chemically joined together
Carbon dioxide,CO2
All substances are made of
atoms
.
Atoms
are the smallest part of an element
A
mixture
is different elements, molecules or compounds not chemically joined together
Iron and sulfur,FE+S :
An
element
is a substance made of only one
type of atom. e.g. the element gold is only made up of gold
(Au) atoms.
A gold atom
Gold (the element)
Each element has a symbol on the periodic table
Periodic Table
A period is a horizontal row
A Group is the vertical columns
Elements are arranged in ascending order by the atomic number
C1.3 Separating Mixtures
Mixtures is made up of two or more substances (elements of compounds) that are not chemically combined together. E.g Sand, salt and water
A substance made when two or more elements are chemically joined together. E.g Sodium Chloride (NaCl)
Sand is dissolved in water Insoluble Mixture
Filitration is used to separate a liquid and insoluble sand.
Distilation - Used to separate a mixture of different liquids by their boiling point. E.g. ethanol and water
Salt dissolved in water - Soluble mixture
Evaporation - Used to separate a solid that has
dissolved in a liquid.
Crystallisation - used to obtain a soluble substance from a solution
C1.5 History of the atom
SOLID SPHERE MODEL
John Dalton
drew upon the Ancient Greek idea of atoms (the word ‘atom’ comes from the Greek ‘atomos’ meaning indivisible). His theory stated that atoms are indivisible, those of a given element are identical, and compounds are combinations of different types of atoms.
PLUM PUDDING MODEL
Thomson
discovered electrons (which he called ‘corpuscles’) in atoms in 1897, for which he won a Nobel Prize. He subsequently produced the ‘plum pudding’model of the atom. It shows the atom as composed of electrons scattered throughout a spherical cloud of positive charge.
NUCLEAR MODEL
Rutherford
fired positively charged alpha particles at a thin sheet of gold foil. Most passed through with little deflection, but some deflected at large angles. This was only possible if the atom was mostly empty space, with the positive charge concentrated in the centre: the nucleus.
PLANETARY MODEL
NIELS BOHR ~ Schrödinger
stated that electrons do not move in set paths around the nucleus, but in waves. It is impossible to know the exact location of the electrons; instead, we have ‘clouds of probability’ called orbitals, in which we are more likely to find an electron
QUANTUM
MECHANICAL MODEL
James Chadwick
bombarded
beryllium atoms with alpha particles. An
unknown radiation was produced. Chadwick interpreted this radiation as being composed of particles with a neutral electrical charge and the approximate mass of a proton. neutron. With the discovery of the neutron, an adequate model of the atom
became available to chemists.
C1.8 Electronic structures
Opposites attract. Protons are
+
and electrons are
–
charged. Electrons will occupy the lowest energy levels first (the shells nearest the nucleus/first shell) unless these shells are already full.
1st shell - capacity = 2
2nd shell - capacity=8
3rd shell - capacity=8
4th shell - capacity=3
:
use the bottom number to determine how may crosses drawn because its the electron number
