- Created by: Conorcog
- Created on: 02-06-18 21:04
Structure of the Atom
The atom is made up of three types of sub-atomic particles: protons, neutrons and electrons. The atom is neutral because it has the same amount of positive protons and negative electrons.
Protons: A proton has a positive relative charge of one. It is found in the nucleus with the neutron. The atomic number is the amount of protons in an atom. Sometimes they are equal to the amount of neutrons, but most of the time there are less protons than neutrons in an atom. The proton has a relative mass of 1
Neutrons: A neutron has no charge. It is found in the nucleus with the proton. The amount of neutrons is found by taking the atomic number from the mass number. The neutron number is always equal or higher than the proton number. In ions the number of neutrons is what defines the element, so we do not take it away. The neutron has a relative mass of 1.
Electrons: An electron has a negative relative charge of one. They are found in shells (orbitals) that orbit the nucleus. The amount of electrons is the same as the amount of protons, so it is the atomic number. If we take away or add electrons we can make ions. The electron has a relative mass of 1/1836, or 1/2000 simplified.
Ions and Solubility
Ions: Atoms want to obtain full outer shells. To do this they trade electrons, creating ions. Ions are like noble gases as they have full outer shells. As such, they are stable. This means that they are good insulators, have a higher melting point and are harder.
Ionic Bonding: This is the name of when atoms trade electrons to become ions. If an atom gets rid of electrons, it loses the negative charge those electrons had. As a result, it is a postive ion. We write this by listing the element then the amount of charge it has changed, then the + or -. Example: Mg2+ because Magnesium has 2 electrons in its final shell it wants rid of.
Solubility: If a substance is soluble it will dissolve in a given amount of liquid (called the ‘solvent’). Different substances have different solubilities. If a substance can dissolve in water we call it water soluble. Temperature and Pressure mainly affect solubility.
Reactions with Water
Lithium (Li) - Floats, Gives out Heat, Creates a colourless solution (Lithium Hydroxide) and a gas (Hydrogen), Moves around in trough, Slowly Dissolves.
Sodium (Na) - Same as Lithium but also forms a ball as it gives out more heat and dissolves faster.(Sodium has a more vigerous reaction than Lithium)
Potassium (K) - Same as Sodium but also burns with a purple flame and its heat can evaporate water. (Potassium has a more vigerous reaction than Sodium)