Chapter C1 Atomic Structure Flashcards
What is an atom?
The smallest part of a chemical element that can exist
What is an element?
Substance made of one type of atom
What is the law of conservation of mass?
The total mass of the products equals the total mass of the reactants
What is a mixture?
A mixture is made up of two or more substances that are not chemically combined together
What is a compound?
A substance formed when two or more elements are chemically bonded together
What are the state symbols?
S- solids
G-gas
L-liquids
Aq- aqueous solution
What are differences between mixtures and compounds?
Compounds have a fixed composition whilst mixtures do not
Compounds require separation by chemical reaction- mixtures do not
Compounds have chemical bonds between atoms- mixtures do not
What is the atomic number?
Number of protons in an element?
What is an ion?
A charged atom or group of atoms
What is an isotope?
Atoms of the same element with a different number of neutrons
How do you calculate the mass of neutrons?
The mass number- the atomic number
How is an atom negatively charged?
If there are more electrons than protons
How is an atom positively charged?
If there are more protons than electrons
Describe the basic structure of an atom
Nucleus containing protons and neutrons with electron shells orbiting it
Describe the technique of filtration?
If you have one soluble substance and one insoluble, add water so one dissolves into the water. Then put it through filter paper. The insoluble one will then be on the filter paper, whilst yeh soluble one will pass through with the solvent
What is filtration used for?
To separate substances that are insoluble in a particular solvent, from substances that are soluble in the solvent
What is crystallisation used for?
To separate absolute from a solvent
Describe the process of crystalissation
Put the solution over a heat source- the solvent will evaporate leaving the solute behind
What is distillation used for?
To separate solvent and a solute without losing the solvent
Describe the process of distillation
The solution is placed over a heart source. The solvent evaporated, and rises into a condenser. This has a cooler temperature and so changes the state of the water vapour back into a liquid. This then means you will have a separated solute and solvent
What is fractional distillation used for?
This is used to separate two liquids with different boiling points
Describe the process of fractional distillation
A solution is heated to a specific boiling point, at which time one of the liquids begins to evaporate. This vapour then rises into a fractioning column, where cool glass beads ensure that if the other liquid has begun to evaporate it condenses. The gas then passed into a condenser and is collected separately
What is chromatography used for?
Used to separate and identify substances from mixtures in a solution
Describe the process of chromatography
A piece of chromatography paper has a line drawn on it. The solution is then spotted onto the line at separate points, this is then placed in a solvent, and the solvent soaks up the paper, running through the spot of the solution. The relative solubility if the components displays how far up the paper they travel, with the more soluble substances travelling further up the paper
Who first came up with the idea of the atom?
Greeks
What did John Dalton do?
Suggested substances were made up of atoms
Suggested atoms rearranged in reactions
Suggested they could not be split
What did Geiger and marsden do?
Alpha particle experiment- fired alpha particles at golden foil. They expected them to go straight through- some of the alpha particles rebounded tho- this meant something in the middle was positively charged- the electrons were orbiting around a nucleus which contained dense protons
What did J.J Thompson do?
Discovered the electron
Found that the beams of particles were attracted to positive charge and so had to be negatively charged.
This proved Dalton was wrong and electrons were embedded in an atom. He suggested the plum pudding model
What did Bohr suggest?
Found that the light given out when atoms were heated had specific energy amounts- suggested electrons orbited in shells
What did James Chadwick do?
Neutrons were discovered as the nucleus had a missing mass- James Chadwick did an experiment only explainable by neutrons
What are the charges of a proton, neutron and electron?
-1
0
1
What is the mass number?
The number of protons+ neutrons
What is electronic strutcture?
A set of numbers to show the arrangement of electrons in their shells
What is the maximum amount of electrons in the first, second and third shell?
2
8
8
