Combined chemistry

• Ice --> steam = sublination
• Ice --> water = melting
• water --> steam = boiling
• The freezing point of water is 0 degrees Celsius, while its boiling point is 100 degrees Celsius.
• What state is this?

  Solid

  
• What state is this?

  Liquid

  
• What state is this?

  Gas

  
• What are the limitations of the particle model?


  1 Doesn't show forces

  2 Doesn't show size or space between particles
• Shell: The path an electron follows depicted as a circle.
• Only 8 electrons can fit in each shell
• The first shell can only have 2 electrons
• A physical change


  Where no new substance is produced.
• A chemical change

  Where a new substance is produced.
• The big number on an element

  Atomic mass number(protons+neutrons)
• The small number on an element

  Atomic number (protons)
• Isotopes are atoms with different numbers of neutrons but the same protons, so they have the same atomic number.
• Covalent bonds occur between non-metals
• Ionic bonding occurs between metals and non-metals
• Neutrons do not carry any electrical charge.
• Protons have a positive charge and electrons have a negative charge.
• An atom has a nucleus containing protons and neutrons surrounded by electrons.
• In a compound, the elements share electrons to make molecules
• Ion


  Electrically charged particles formed when Atoms lose or gain electrons
• A covalent bond is a shared pair of electrons between two non metals when the atoms get close enough to share electrons.
• Allotrope an element that exists in different forms but in the same physical state.
• Size of an atom


  $1\times 10^{-10}m$
• Covalent bonds involve shared electrons.
• Simple covalent molecules like graphite and graphene have high melting points and boiling points because the bonds between them are strong.
• Ionic bonds are formed when a metal loses electrons to form a positively charged ion
• Non-metal gains electron to become negatively charged ion
• Oppisite charged ions attract each other.
• Ionic compound: A compound that contains ions, which are atoms or molecules that have gained or lost electrons.
• What do plant cells have that animal cells don't have?

  cell wall and vacuole