Atomic Structure and the Periodic Table Flashcards
What is in the nucleus?
Protons and Neutrons
Electrons _____ the nucleus in ______ ____
Orbit
Electron shells
Atoms have the same number of _______ and _______
Protons
Electrons
Why do atoms have no charge?
The positive charge of the protons cancel out the negative charge of the electrons
Neutrons have no charge
Mass of neutron:
1
Mass of proton:
1
Mass of electron:
Very small 0.000000005
Charge of proton:
+1
Charge of neutron:
0
Charge of electron:
-1
What is the mass number of an element?
The total number of protons and neutrons in the nucleus of the atom
What is the atomic number of an element?
The number of protons in the nucleus of the element
What are isotopes?
Different forms of an element, that have the same number of protons but a different number of neutrons
What is a compound?
A substance made from 2 or more elements that are chemically bonded
What is needed to separate compounds into its original elements?
A chemical reaction
What is a mixture?
Elements that are mixed together - no chemical reaction
Can a mixture be seperated out?
Yes by physical methods
Properties of ________ are usually different from the properties of the ________ element
Compounds
Original
Properties of ________ are a mix of the properties of the ________
Mixtures
Elements
What is chromatography used to separate?
Mixtures (of coloured compounds such as dyes)
What is the solvent?
The liquid
Why use a pencil to mark during chromotography?
Its insoluble
Why should the compounds NOT touch the solvent?
The compounds will dissolve in it
What will the movement of a dye be if its insoluble?
It will stay on the baseline
What is filtration used to separate?
Insoluble solids from liquids
What is evaporation used to separate?
Solids from solutions
What dish is used during evaporation?
An evaporating dish
What is crystallisation used to separate?
Soluble solids from solutions if the salt decomposes when heated
When does evaporation not work?
If the salt decomposes when heated
During crystallisation what do you do after evaporating the solution to form salt crystals?
Filter the crystals out of the solution
How do you separate rock salt?
Dissolve the salt in water
Filter the mixture - removes rock
Evaporate the water - leaves salt as crystal
What is distillation used to separate?
Mixtures which contain liquids
What is simple distilliation used to separate?
A liquid from a solution
What is fractional distillation used to separate?
A mixture of liquids (more than 1)
Simple distillation can only be used to separate things with …….
Very different boiling points
What happens during simple distillation?
The solution is heated - liquid with lowest boiling point evaporates
Vapour is cooled by a condenser and collected
What happens during fractional distillation?
Heat the mixture
Different liquids evaporate at different temps
When one liquid evaporates at its boiling point, it will reach the top of the column
Other liquids that start evaporating will only get a certain way before condensing
John _______ said that all matter was made up of ______ which are _____ ______
Dalton
Atoms
Solid spheres
What did JJ Thompson conclude?
The plum pudding model
Who thought of the plum pudding model?
JJ Thompson