Flashcards in Atomic Structure Deck (26):
What is an element?
An element is one type of atom in a group
What is a compound?
A compound is when two or more elements of different types chemically bond together. In a specific compound the number of each element is fixed
What is a molecule?
A molecule includes any element that is chemically bound
What is the relative charge of a neutron, proton and electron?
What is an isotope?
They are different forms of the same element which have the same amount of protons but different amount of nuetrons
What can physical separation techniques break down?
What is filtration used for?
To separate an insoluble solid from a liquid
What is crystallisation used for?
Used to separate a soluble solid from a liquid
What is simple distillation?
Distillation is used to separate a liquid from a solid if we want to keep the liquid
What is fractional distillation
The separation of a mixture of liquid which must have two different boiling points.
How does distillation take place?
You evaporate the liquid like crystallisation then you put the liquid vapour into a condensing tube the condenser uses cold water flowing around the tube to cool the vapour down back into liquid into a beaker. A thermometer is also used it shows us that the temperature is rising.
Give a use of simple distillation?
To make drinking water
What equipment is different between simple and fractional distillation?
Fractional distillation has a long column with hundreds of glass beads inside this is called the fractionating col
what does the fractionating column do?
because the water with the lower boiling point can evaporate easier than the other when both water vapours travel up the tube they condense and fall back into the flask this repeated process increases the amount of the lower boiling point vapour in the fractionating column.
What is paper chromatography?
Allows us to separate substances based on their different solubility
What are the phases in chromatography?
the paper-stationary phase because it doesn't move
The solvent-the mobile phase
How does paper chromatography work?
it works because each of the mixture will be attracted to the stationary phase to a different extent. Chemicals that are attracted ore won't move very far.
How do can you read the results of a chromatography test?
A pure chemical will produce a single spot in all solvents whereas a chemical in the mixture may separate into different spots depending on the solvent.
What does the plum pudding model look like?
An atom is a ball of positive charge with negative electrons embedded in it.
What happened in the year 1897?
Scientists discovered tiny negative particles in the atom they called them electrons
What happened in the year 1897?
Scientists discovered tiny negative particles in the atom they called them electrons. They have an internal structure
Describe the alpha scattering experiment
Tiny alpha particles with a positive charge were fired at the thin gold foil most of the alpha particles went through the foil without changing direction but some changed direction even bounced back.
How did scientists interpret the results of the alpha particle experiment?
They then believed atoms were mainly made up of empty space so they knew the plum pudding was wrong and because some were deflected the centre most be positively charged so the alpha particles would repel away from it. Because some atoms were sent straight back this told them the centre contained a great deal of mass.
What charge does an atom have?
What is the radius of an atom?