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Slide 1

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Chemistry Revision
Year 10 mocks…read more

Slide 2

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C1.1 fundamental ideas…read more

Slide 3

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Atoms, elements and compounds
· 100 different elements which all substances made from
· Each element made of one types of atom
· Atoms represented by chemical symbols, iron = Fe and oxygen = O
· Atoms = tiny nucleus surrounded by electrons
· When elements react, atoms join with atoms from other elements,
forming compounds (formed when 2 or more elements combine
together)…read more

Slide 4

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Atomic structure
· Nucleus at the centre of atom contains two types of particle ­ protons and neutrons
· Protons = positive charge and neutron= no charge
· Electrons tiny negatively charge particles that move around nucleus
· Atom has no overall charge ­ no. of protons = no. of electrons and charges are equal
and opposite (proton +1 and electron -1)
· All atoms contain same no. of protons ­ atomic number (arranged by atomic number
in periodic table) ­ also no. of electrons in atom
· Mass number = total no. of particles in nucleus of atom ­ so no. of protons + no. of
neutrons…read more

Slide 5

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Arrangement of electrons in atoms
· Each electron in atom is in an energy level ­ energy levels represented in shells (with
electrons in lowest energy level closest to the nucleus)
· First shell can hold 2 electrons, the second shell can hold 8 electrons
· Electrical structure of neon is 10 electrons, 2,8 and sodium has 11 electrons, 2,8,1
· Elements in the same group in periodic table have same number of electrons in outer
shell
· E.g. group 1 has 1 electron in outer shell, group 1 = lithium, sodium, and potassium
(examples)
atoms of unreactive noble gases (group 0) all have very stable arrangements of
electrons…read more

Slide 6

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Forming bonds
· When different elements combine compounds form
· When metal react with non-metals ­ ions form
· Metal atoms lose 1 or more electrons to form positively charged ions
· Non-metal atoms gain 1 or more electrons forming negatively charged ions
· The oppositely charged ions attract each other strongly and the compound
has ionic bonds
· Chemical formula of ionic compound tells ratio of ions in compound
· When non-metal combine ­ atoms share electrons forming covalent bonds
· Chemical formula of molecules tells us no. of atoms that have bonded
together in molecule
Ionic bonding
Covalent bonding…read more

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Slide 10

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