MATERIALS AND THEIR STRUCTURES

• Elements

  A substance made by only one type of atom
• Ernest Rutherford’s NUCLEAR MODEL of the atomic structure was proposed


  1911
• Negative and negative charges

  Repel
• Protons and neutrons have much more mass than electrons
• BURNING / COMBUSTION

  Metal + oxygen → Metal oxide
• WORD EQUATIONS FOR 2 ELEMENTS + OXYGEN: magnesium + nitrogen + oxygen —> magnesium nitrate
• METALS WITH ACIDS

  Metal + Acid —> Salt + Hydrogen
• Charges of particles in an atom

  • Protons (positive)
  • Electrons (negative)
  • Neutrons (neutral)
• IRON WITH WATER (RUSTING)


  Iron(3) + water + oxygen —> Hydrated iron (3) oxide
• Planetary model


  Proposed by Niels Bohr in 1913
• Reactants: substances that are destroyed by chemical reactions
• An atom contains a nucleus in the centre surrounded by shells. The nucleus has protons and neutrons while electrons surround the nucleus in the shells
• METAL HYDROXIDE WITH ACIDS

  Metal hydroxide + Acid —> Salt + Water
• CHEMICAL CHANGES: Chemical changes produce a new substance and are accompanied by energy change. Chemical changes are irreversible
• ENDOTHERMIC REACTIONS: Endothermic reactions absorb heat, resulting in a colder product
• HOW TO DETECT CHEMICAL CHANGES: forms a new substance, forms a gas (bubbles / fizz), pH changes, temperature changes, color changes, precipitate forms
• Rutherford’s Alpha particle scattering experiment‘s conclusions

  1. There is a positively charged nucleus in the middle

  2. Inside an atom is mostly empty space

  3. Electrons move around the nucleus in a circular orbit
• METALS AND WATER

  Metal + water → Metal hydroxide + Hydrogen
• Positive and negative charges

  Attract
• ATOMS: particles that cannot be broken down by any chemical reactions
• PARTS OF CHEMICAL REACTIONS

  Reactants —> Products
• Electrons have almost no mass
• METAL OXIDES WITH ACIDS

  Metal oxide + Acid —> Salt + Water
• PHYSICAL CHANGES: Physical changes do not produce a new substance and only change the state of a substance. Physical changes are reversible
• GAS TESTS: Hydrogen makes a squeaky pop sound when a lighted match stick makes contact, Carbon dioxide makes limewater turn milky, Oxygen relights a glowing splint
• Positive and positive charges

  Repel
• Protons and neutrons have the same mass
• Compound

  A substance made by more than one type of atoms or elements that are chemically bonded together
• Products: substances are created by chemical reactions
• WORD EQUATIONS FOR COMPOUNDS (METAL & NONMETAL): sodium + iodine —> sodium iodide
• METAL CARBONATE WITH ACIDS

  Metal carbonate + Acid —> Salt + Carbon dioxide + Water
• EXOTHERMIC REACTIONS: Exothermic reactions give out heat, resulting in a warmer product
• HEATING / THERMAL DECOMPOSITION

  Metal carbonate —> Metal oxide + Carbon dioxide