Chemistry

• John Dalton, the atom is hard and indestructible

  Billiar Ball Model
• Jj Thomson, electrons are embedded in a positively-charged sphere

  Plum Pudding Model
• Ernest Rutherford, the mass and all of the positive charge of an atom is concentrated in the nucleus

  Nuclear Model
• Niels Bohr, electrons travel around the nucleus in a circular orbit; their energy is proportional to their distance from the nucleus

  Planetary Model
• the electron is a wave; found in orbitals

  Quantum Model
• number of protons in the nucleus; also equal to thw number of electrons, if the atom is neutral

  atomic number
• protons + neutrons

  mass number
• • electron are negatively charged
  • proton are positively charged
  • while neutron are neutral
• • protons in an atom is constant.
  • The number of protons in an atom determines what element it is
• ATOMIC THEORY

  • All matter is made up of atoms
  • All atoms of an element have identical chemical and physical properties
  • Atoms of different elements have different sets of chemical and physical properties
• highly reactive metals; have one excess electron which they tend to lose, thus usually have a charge of +1; usually form compounds with halogens; e.g. Na

  alkali metals
• highly reactive non-metals; lack one electron on their outer shell which they try to acquire from other atoms, thus they usually have a charge of -1; usually form compounds with alkali metals; e.g. Cl

  halogens
• or inert gases; uneactive and very stable elements owing to their full outer shell of 8 electrons; e.g. Ne

  noble gases
• have both metallic and non-metallic properties; e.g. B

  metalloids
• elements t9 the right of the metalloids; e.g. Cl

  non-metals
• all elements to the left of the metalloids (except H); e.g. B

  metals
• atoms of the same element that differ in the number of neutrons

  isotopes
• elements gain or lose electrons so that they will have sane number ss the nearest noble glass

  octet rule
• ion - charged ionanion- negatively‐charged; gain in electrons; electron>protons

  cation- positively - charged ; loss of electrons; electronsprotons
• ionization energy- enery required to remove an electron from an atom
• TYPES OF SOLUTION

  • unsaturated - can still dissolve more solute
  • saturated - already contains the maximum amount of solute
  • supersaturated - used pressure or heat to dissolve more than usual amount of solute
• amount of energy needed to to raise the temperature of a substance by one degree

  specific heat
• hotness or coldness

  temperature
• total kinetic energy or molecules

  heat
• heat lost or gained during a change in temperature

  sensible heat
• heat lost or gained during a phase

  latent heat
• formed by a cation and an anion wherein there is a transfer of electrons so that each atom has the same number of electrons

  ionic compoun
• the compound formed by atoms that share electrons so that each has the same number of electrons as the nearest noble gas

  covalent compound
• CHEMICAL BONDING

  • intramolecular - attraction between atoms in a molecule
  • covalent bond - sharing od electrons between to non-metals
  • ionic bond - transfer of electrons; between metals and non-metals/cations anr anions
  • intermolecular - attraction between molecules
  • London dispersion forces - between two temporarily polar molecules
  • dipole-dipole forces - for polar covalent molecules
  • hydrogen bond - between the H atom and an F, N, or O atom of another molecule
• bonding strength

  1. ionic bonding
  2. covalent bonding
  3. hydrogen bonding
  4. dipole-dipole forces
  5. London dispersion forces