Chemistry C2 GCSE AQA - UNIT 1

Chemistry C2 GCSE (higher), will contain all topics in the AQA C2 exam.

Unit 1, units 2, 3, 4, 5, 6 and 7 to follow soon hopefully.

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Atomic Structure

Atomic Structure

  • Centre nucleus contains protons and neutrons.
  • Protons = POSITIVE CHARGE
  • Neutrons = NO CHARGE
  • Electrons = negative charge
  • Therefore the overall atom has NO OVERALL CHARGE
  • Atoms of the same element contain the SAME NUMBER OF PROTONS
  • This is called the PROTON NUMBER
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The Arrangement of Electrons in Atoms

The Arrangement of Electrons in Atoms

  • Electrons shown on diagrams as dots or crosses
  • Lowest energy level holds TWO ELECTRONS
  • The rest hold EIGHT ELECTRONS
  • Elements in the same group on the periodic table hold the SAME number of ELECTRONS in their HIGHEST ENERGY LEVEL
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Chemical Bonding

Chemical Bonding

  • Nobel gases are UNREACTIVE - as their atoms are in a stable arrangement (Group 8)
  • Other elements can achieve this by GAINING or LOSING electrons to form ions
  • An ion is an atom/group of atoms that has LOST/GAINED electron/s.
  • Therefore it is CHARGED
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Ionic Bonding

Ionic Bonding

  • Holds OPPOSITELY CHARGED ions together in GIANT STRUCTURES
  • Strong ELECTROSTATIC forces of attraction act in all directions.
  • Each ion is surrounded by opposite charge - held in place
  • Example of Ionic Bonding -
    • Mg (2+) + Cl (-) > MgCl(2) as twice as many chloride atoms are needed
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Ionic Compounds and High Melting Points

Properties of Ionic Compounds

  •  
    • HIGH melting points - tight structure, strong electrostatic forces
    • A LARGE amount of energy is needed to break these forces to overcoem the attraction
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Covalent Bonding

Covalent Bonding

  • If BOTH atoms need to GAIN electrons to get a full outer energy level.
  • They SHARE electrons in a covalent bond

Properties

  • LOW melting/boiling points
    • Not much energy needed to break inter-molecular forces
  • INSULATORS of electricity, (do not conduct)
    • No free moving charged particals (ions)
  • WEAK inter-molecular forces
  • STRONG intra-molecular forces
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Bonding in Metals

Bonding in Metals

  • Atoms in a metallic element are ALL the SAME size.
  • They form GIANT STRUCTURES, layers of atoms arranged in regular PATTERNS
  • The electrons in the highest energy level DELOCALISE - results in strong electrostatic forces between these electrons and the positively charged metal ions
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Comments

Grace

protons and neutrons are in the nucleus, electrons are in shells around the nucleus

OneTooManyAnOpinion

Grace wrote:

protons and neutrons are in the nucleus, electrons are in shells around the nucleus

Yes?

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