Created by helensellers75
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Copied to Note by helensellers75
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How is it made? Most of mass is in the nucleus Numbers
IsotopesExample:
The electrons Shells Organised
Relative Atomic MassChlorine
Relative formular massInvolving Crystallisation
The Mole Measure of an amount of substance 6 x 10 (23) = Avagadro Number Detail +
Calculating mass of 1 mole Ar in grams Mr in grams:
Molar Volume of Gas
Amount of Gas
The only atom with no neutrons is the simplest isotope of Hydrog
Proton: Charge +1 Mass 1 Electrons: Charge -1 Mass 1/1836 Neutron: Charge 0 Mass 1
Atomic number= no of protons Mass number = number of protons + neutrons 35 Cl 17
Isotopes are atoms with some atomic number but different mass numbers. They contain same number of protons but different numbers of neutrons
Isotope Proton Neutrons Hydrogen-1 1 0 Hydrogen-2 1 1 Hydrogen-3 1 2
Same as proton number Carbon- 6 electron Sodium- 11 electrons
Electrons exist around the nucleus in different energy levels called electron shells
1st Shell = 2 2nd Shell= 8 3rd Shell = up to 18
Chlorine has 2 isotopes: Chlorine-35 Chlorine-37 Total mass of 100 atoms= (75 x 35)+ (25 x 37) = 3550 Average mass= 3550/100 = 35.5 Ar = 35.5
Hydrogen (H2) 1 x 2 = 2 H2O 1 x 2 + 16= 18
Hydrated Mg Sulphate MgSO4. 7H2O - calculate Mr of MgSO4 = 24 + 32 + (4 x 16)= 120 Add 7 x Mr of H2O = 7 x 18= 126 Mr = 120 + 126 = 246
1 Mole is the amount that contains 6 x 10 (23) particles of the substance
Sodium Chloride is an ionic compound and therfore doesn't contain molecules
1 mol of Na contains AN atoms of Sodium 1 mol of H2 has AN molecules of hydrogen 1 mol of NaCl contains AN formulae of Sodium Chloride
Ar Mass H 1 1g O 16 16g Na 23 23g
Mr Mass H2 1 x 2 2g H2O 2 x 1 + 16 18g
1 mol has a volume of 24 dm (3) Volume = amount x 24 H 3 mol 3 x 24 = 72 CO2 0.25mol 0.25 x 24 = 6
Amount of gas (moles) = volume/ 24 Methane 225.6 dm 225.6/24= 9.4 mol Oxygen 1200 cm (3) /1000 1.2/ 24 = 0.05 mol
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Chapter 3: Atomic Structure
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