Unit 1- Atomic Structure and the Periodic Table Flashcards
What is everything made up of
Atoms
What is an element?
A substance that contains only one sort of atom
What is a compound
A substance that contains two or more elements chemically combined
What is the chemical formula for water
H2O
What can compounds be separated into?
Their elements
What is a mixture
A substance that consists of two or more elements or compounds which are NOT chemically combined
The components in a mixture retain their?
Properties
What are the 5 main physical separation processes?π¬πβοΈπ’π
- Filtration π¬
- Crystallisationπ
- Simple distillation βοΈ
- Fractional distillation
- Chromatography π
What is filtration? π¬
The separation of soluble solids from insoluble solids
Eg- salt (soluble) and sand (insoluble)- dissolve the salt in water and filter
What is crystallisation?π
Used to obtain a soluble solid from a solution
Eg salt crystals can be obtained from a solution of salt water
Simple distillation is?βοΈ
Used to obtain a solvent from a solution
Eg- distillation of water (see required practical)βοΈβοΈβοΈβοΈπ§π§π§π§
What is fractional distillation?π’
Used to separate mixtures in which the components have different boiling
Eg- oxygen and nitrogen can be obtained from liquid air because they have different boiling points
What is chromatography?ππππ
Used to seperate different soluble, coloured components of a mixture
Eg- the different colours added to a fizzy drink
Who and when discovered the electron
Thomson in 1898
What was the βplum puddingβ model by Thomson?πͺ
The atom contained tiny, negative electrons surrounded by a sea of positive charge
What did the Geiger and Marsden experiment consist of?
They bombarded a thin sheet of gold with alpha particles.
The majority of the particles passed straight through the atoms, but some were deflected.
What was the conclusion of the Geiger Marsden experiment ?
The positive charge in an atom must be concentrated in a very small area ie THE NUCLEUS π
What was the model called after the Geiger and Marsden experiment?
The nuclear model of the atom
What did Bohr conclude?
That electrons must orbit the nucleus at specific distances, otherwise they would spiral inwards!ππππππ
Later experiments showed that the nucleus was made up of what
Smaller particles-
Protons +
Neutrons no charge
What is the radius of an atom
0.1nm OR 1 x 10-10m
What are the relative masses of the subatomic particles
Proton-1
Neutron-1
Electron-0.0005
What are the relative charges of the subatomic particles
Proton +1
Neutron 0
Electron -1
Atoms have no overall?
CHARGE + -