Atomic Structure and Periodic Table Flashcards
What does the atom consist of
Protons
Neutrons
Electrons
What is atomic number
Number of protons
Mass Number
Number of protons AND Neutrons
What is an element
A group of atoms with the same atomic number
What is an istotope
An element with the same amount of protons and electrons, but a different amount of neutrons
What is Relative atomic mass
Average mass taking into account the different masses and abundances of all the isotopes that make up the element
How do you calculate the relative atomic mass
(Abundance X Atomic number) +(Abundance X Atomic number)
/Sum of abundances of all isotopes
Elements react to form
Compounds
Compound
Substances of two or more elements, the atoms of each are in fixed proportions and held together by chemical bonds
Mixtures
A collection of elements or compounds that are not chemically bonded together
Methods to seperate mixtures (3)
- Chromatography
- Filtration and Crustallisation
-Distillation
How do you perform chromatography
- Draw a line in pencil and a pen dot on filter paper above the water level
- Place a lid so it doesnt evaporate
- Each different dye in the ink will move up the paper at different rates
- When it’s done take it out and leave it to dry
-End result is a chromatogram
What is filtration
Seperating insoluble solids from liquids
How to perform filtration
- Roll up filter paper
- Place in a funnel over a beaker
- Pour solution with insoluble solid in and wait
-Solution should pass through filter paper and be pure
Two ways of seperating soluble solids from solutions
Evaporation, Crystallisation
Describe process of evaporation
-Pour solution into evaporating dish
- Slowly heat the solution. The solvent will evaporate and the solution will get more concentrated. Eventually crystals will start to form.
- Keep heating until you only have dry crystals
Describe the process of crystallisation
- Pour the solution into an evaporating dish
- Heat for a bit
- When you see crystals, remove from heat and leave to cool
- Filter the crystals out of the colution and leave in a warm place to dry.
How can you use filtration and crystallistaion to seperate rock salt
1- Grind the rock salt to ensure the salt crystals are as small as possibkle and can dissolve easily
2- Place the salt in water and stir until the salt dissolved
3- Filter the solution
4- Evaporate the water from the salt so that it forms dry crystals
What is simple distillation
The process of seperating out two solutions
Explain the process of simple distillation and two liquids it can seperate
Seperating pure water and sea water
-Solution is heated to the lowest boiling point of the two solutions
- The vapour condenses and is collected in a beaker whilst the rest of the solution is left behind
When do you use fractional distillation
To seperate a mixture of three or more liquids
How do you carry out fractional distillation
- Put your mixture in a flask and put a fractionating column ontop
- Heat the flask and the liquid with the lowest boiling point will evaporate first. It will evaporate, rise up, go through a condenser and then is collected in a test tube
What was Thompson’s theory of the atom
Plum pudding model- Atom’s weren’t solid spheres but positive balls with negative electrons
What was Rutherford’s theory of the atom
After the gold foil experiment he knew there was a dense positively charged nucleus in the middle with electrons in a ‘cloud ‘outside it.
