C1- Atomic structure Flashcards
Atom definition
Smallest part of an element that can exist
Element definition
Substance made up of only one type of atom
Compound definition
2 or more elements chemically combined in fixed proportions
Why are the elements in groups?
A group contains elements with similar chemical properties
Which elements exist as molecules with 2 atoms joined together?
Iodine, bromine, chlorine, fluorine, oxygen, nitrogen, hydrogen
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Chemically balanced definition
Same number of each atom on both sides of equation
Law of conservation of mass
Total mass of products equal to total mass of reactants
What are the 4 state symbols?
(s) Solid
(g) Gas
(l) Liquid
(aq) Aqueous
What is an aqueous solution?
A substance dissolved in water
Mixture definition?
Two or more substances that are not chemically combined
Filtration
Method?
Product?
Waste?
Pour mixture through filter paper in a funnel
Filtrate that passes through the paper
Insoluble solids stay on the filter paper
Evaporation
Method?
Product?
Waste?
Heat mixture to dryness in evaporating basin
Residue left in basin
Evaporated solvent
Simple distillation
Method?
Product?
Waste?
Heat mixture gently until only solvent evaporates, vapours condensed
Condensed solvent
Dissolved solids
Crystallisation
Method?
Product?
Waste?
Heat mixture, partially evaporate solvent in evaporating basin. Cool slowly for crystals
Crystals in basin
Evaporated solvent
Fractional distillation
Method?
Product?
Waste?
Heat; liquids vaporise to fractionating column with temp gradient. Lowest boiling point liquid reaches condenser, others fall back.
Condensed liquid with lowest boiling point
Liquids with higher boiling points
Paper chromatography
Method?
Product?
Waste?
Place samples on filter paper that touches a solvent. Substances travel dif distances on paper
None
All- used for analysis, products not recovered
Dalton
Model name?
Key features?
Atomic model
-substances made of atoms
-atom is smallest part of any element
JJ Thomson
Model name?
Key features?
Plum pudding model
-Discovered electron
-Found relative mass & charge of electron
-Embedded in positive cloud
Rutherford
Model name?
Key features?
Nuclear model
-Discovered tiny, positive,massive nucleus
- Electrons orbit nucleus
Bohr
Model name?
Key features?
Planetary model
-Electrons orbit at fixed distances
-Electron shells have different energy levels
Chadwick
Model name?
Key features?
Proton neutron model
-Discovered neutrons have no charge and same mass
Alpha particle experiment
Who?
What happened?
Proved?
Rutherford fired alpha particles at thin gold foil
Particles scattered and some reflected back
Proved tiny, massive, positive, central nucleus
Proton
Symbol?
Relative mass?
Relative charge?
Location?
p+
1
+1
Nucleus
Neutron
Symbol?
Relative mass?
Relative charge?
Location?
n
1
0
Nucleus
Electron
Symbol?
Relative mass?
Relative charge?
Location?
e-
almost 0
-1
Electron shells
Radius of typical atom?
Size of nucleus?
10 to power of -10m
1/1000 of the atom
Where is the mass of an atom concentrated?
What is the charge of an atom?
Nucleus
No charge
Atomic number definition?
Number of protons in each atom
Mass number definition?
Number of protons and neutrons in nucleus of atom
How to work out number of neutrons?
Mass number- atomic number = number of neutrons
Isotopes defintion?
Atoms of the same element (same no. of protons) with dif no. of neutrons
Ion definition?
A charged atom or group of atoms
Isotopes have the same?
-Number of protons
-Number of electrons
-Chemical properties
Isotopes have different?
-Number of neutrons
-Atomic mass
-Density
-Melting & boiling points
What is relative atomic mass?
Weighted mean of the masses of the isotopes
