Observations and Ions

• For Aluminum (Al), the electron configuration is 2,8,3 and forms on ion with a +3 charge by losing 3 elections.
• Oxygen's (O) electron configuration is 2,6 and forms an ion with a -2 charge, gaining 2 electrons.
• Chlorine's (Cl) electron configuration is 2,8,7 and forms on ion with a -1 charge, gaining 1 electron.
• Beryllium's (Be) electron configuration is 2,2 and forms on ion with a +2 charge losing 2 electrons.
• Sulfur's (S) electron configuration is 2,8,6 and forms on ion with a -2 charge, gaining 2 electrons.
• Metals lose electrons to form positive ions.
• Non-metals gain electrons to form negative ions.

Element Observations and Electronic Structure

• Lithium (Li) fizzes, floats and moves on the surface of water, and turns universal indicator blue during reaction with water
• Sodium (Na) exhibits the same observations as lithium, and the metal melts into a ball.
• Potassium (K) exhibits all the obervations of Sodium, in addition to lilac flame. The outer shells get further from the nucleus.

Reactivity Trend

• Reactivity increases down the group, because the outer shell gets further from the nucleus.
• Sodium's outer shell is further from the nucleus; thus, the outer electron is less attracted to the nucleus, and lost more easily, making Sodium (Na) more reactive than Lithium (Li).

Key Definitions

• Atom: The smallest part of an element that can exist.
• Molecule: 2 or more atoms joined together
• Element: A substance containing only one type of atom, found on the Periodic Table.
• Compound: 2 or more elements chemically bonded together with a chemical formula.
• Mixture: 2 or more elements/compounds not chemically bonded and does not have a chemical formula

Solutions

• A solute is dissolved in a solvent and the mixture is a solution.

Crystallisation

• Heat up the solution until crystals form, then leave the water to evaporate Filtration: filter paper allows water and any dissolved substances through, separating the solid. Distillation: Allows to tell measure the boiling point of a liquid
• Heat the mixture until one substance evaporates, the vapour moves through a condenser and then condenses.

Isotopes

• Isotopes are different atoms with the same number of protons, but different numbers of neutrons.

Atomic Timeline

• 1890: Dalton proposed that atoms are spheres.
• JJ Thompson: discovered Electrons and proposed the Plum Pudding Model.
• Rutherford determined that most of any atom is empty space and discovered the Nucleus, determining that it contains most of the mass and the positive charge.
• Bohr discovered that Electrons exist in shells at specific distances from the nucleus.
• Rutherford discovered protons.
• Chadwick discovered neutrons.

Bonding & Structure

• Giant Ionic Lattice materials are composed of metals and non-metals in an alternating lattice of positive and negative ions with strong electrostatic forces between oppositely charged ions.
• Small Covalent Molecules are non-metals held together by strong covalent bonds to make molecules with weak intermolecular forces between them.
• Polymers are non-metals with repeating units in a chain connected by strong covalent bonds, and weak intermolecular forces between chains.
• Fullerenes and Nanotubes, such as balls and tubes, are carbon atoms joined by strong covalent bonds, but have weak intermolecular forces between the molecules.
• Diamond forms carbon atoms bound by strong covalent bonds.
• Silicone Dioxide bonds silicone and oxygen atoms by strong covalent bonds.
• Graphite forms carbon atoms by strong covalent bonds into layers with weak intermolecular forces between the layers, and delocalised electrons.
• Graphene is a single layer of graphite.

Metals & Alloys

• Metals found on the periodic table use strong electrostatic forces between positive ions and delocalised electrons.
• The metal atoms exist in layers
• Alloys are like metals, but with atoms of different sizes, wich disrupting the layers so they can't slide over each other.
• Noble gases (Group 0) use very weak forces between atoms

Electrical Conductivity

• Substances conduct electricity if they have charged particles that can move through the structure.
• Ions
• Delocalized electrons
• Solids at room temperature have high melting/boiling points, needing a lot of energy to be broken, due to strong bonds/forces.
• Gases (or liquids) at room temperature have low melting/boiling points, needing little energy due to weak forces.

Ionic Bonding

• When compounds form, atoms become chemically combined.
• This involves a force of attraction holding them together, known as a bond with three types: covalent, ionic, and metallic.
• Ionic bonds form between metal and non-metal atoms.
• Atoms involve the transfer of electrons from one atom (the metal) to another atom (the non-metal.)
• When atoms loose or gain electrons, atoms become stable with with full outer shells of electrons.
• They become stable with the same electron configuration as a noble gas (Group 0)
• Covalent bonding occurs for non-metals, where lattices do not form.
• Instead, small numbers of molecules with shared electrons are formed with are made in between the atoms.

Nanoparticles

• Nanoscience studies structures that are 1-100nm in size.
• Most nanoparticles are made up of a few 100 atoms.
• Nanoparticles have a very large Surface Area to Volume ratios when compared to the same material in bulk.
• Surface area increases and the surface area to volume ratio increases as particle volume decreases.
• Uses of nanoparticles: catalysts, drug delivery, electronics, and suncream.