Chapter 3: Atomic Structure - created from Mind Map

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How is it made?

Most of mass is in the nucleus

Numbers

Isotopes

Example:

The electrons

Shells

Organised

Relative Atomic Mass

Chlorine

Relative formular mass

Involving 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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