unhinged math :(

• Physical change


  A change in which no new substances are formed (change of state, dissolving)
• Physical change


  • No new substances are formed
  • Changes are reversible
  • Constituent substances can be obtained during separation techniques
• Chemical change


  A change in which one or more new substances are formed
• Chemical change


  • Changes usually not easily reversed
  • Reactants cannot be obtained easily
  • Substances (reactants) react with each other to form new substances (products)
  • Usually energy (thermal, light, electrical) is taken in or given out
  • 2 or more substances chemically combined or substance broken down into 2 or more
  • Common attributes: gas evolved, changed in appearance, precipitation, light observed/change in temp
• All matter are made up of atoms
• Any chemical change involves only a rearrangement of the atoms
• Thermal Decomposition


  Breakdown of compound into simpler substances
• Combustion


  Burning of substance in presence of oxygen to form new compounds
• Precipitation


  Formation of solid when 2 solutions are mixed
• Oxidation (rusting)


  Addition of oxygen to a substance
• Oxidation (respiration)


  Process by which living organisms get energy
• Photosynthesis


  Green plants transform light energy into chemical energy
• Periodic table


  Elements are arranged according to their proton aka atomic number
• Atoms in the same group

  Have the same number of valence electrons
• Why valence electrons involved in chemical reactions and not the others: Valence electrons are further away from the nucleus as compared to electrons from inner electron shells. Therefore, valence electrons experience weaker electrostatic forces of attraction from the protons in the nucleus
• Noble gases


  Relatively stable chemically, inert and do not bond with other atoms (their valence shells are completely filled)
• Chemical bonding


  The electrostatic force of attraction between particles/sub-atomic particles
• Only valence electrons are involved in chemical bonding
• Whether atoms form chemical bonds depends on the electronic configuration of the atoms
• Elements that are diatomic

  • Hydrogen
  • Nitrogen
  • Oxygen
  • Group 17 elements
• Ion


  A charged particle that is formed when an atom loses or gains electrons
• Sodium atom

  Reacts by losing an electron to form sodium ion, a positive ion known as cation. Metal atoms tend to lose electrons and form positive ions.
• Chlorine atom

  Reacts by gaining an electron to form a chloride ion, a negative ion also known as anion. Most non-metal atoms will gain electrons and form negative ions.
• Positively charged stuff have more protons than electrons
• Polyatomic ion


  More than one atom, covalent bonds between their atoms
• Ionic compounds can contain metallic and nonmetallic or both nonmetallic (ammonium chloride) but idk abt both metallic
• Each atom can share its valence electrons
• Covalent bonding


  The electrostatic forces of attraction between the shared pair of negatively charged electrons and the positive nuclei of the 2 atoms. It's formed when NON-METAL atoms share electrons.
• Covalent bonds can be formed between atoms of the same or different elements.
• Neither atom has an ionic charge in covalent bonding.
• Molecule


  An uncharged group of 2 or more atoms held together by covalent bonds.