science

• Mass


  • Measure the amount of matter has
  • Quantity of matter in a body
  • SI unit is kilogram (kg)
• Volume


  • Measure of space occupied by an object
  • Measure of the amount of three dimensional space an object fills
  • SI unit is cubic meter (m3)
• Texture


  • The feel or appearance of the surface
  • It may be rough or soft
• Flexibility


  • Object's ability to bend
  • A measure of how far a material can bend without breaking
• Malleability


  The ability of an object to bend or be hammered into another shape without breaking
• Density


  • A measure of how much mass is contained in a given volume
  • Measure of how "packed" or "crowded" the materials are in a defined area
• Electrical conductivity


  How easily an electrical current flows through a substance or object
• Atom


  • The basic unit of matter
  • Also known as the "building blocks of matter"
• Scanning Tunneling Microscope (STM)


  • A type of microscope that is used to view and scan the surface of the atom
• Leucippus and Democritus


  • "Atoms are physically, but not geometrically indivisible"
• Democritus


  • Believed that any piece of matter can be divided and subdivided into very small particles
• John Dalton


  • Proposed Dalton's Atomic Theory
  • Presented evidence that all matter is made up of small particles
• Dalton's Atomic Model (1803)


  • Also known as "Solid Sphere Theory"
  • Dalton defines an atom as a ball-like structure
  • Atomic nucleus and electrons were unknown at that time
• Dalton's Atomic Model Postulate


  • Elements consists of small particles
  • All atoms of the same element are identical
  • Atoms can neither be created nor destroyed
• Molecule


  • Combination of two or more atoms
  • Forms the smallest unit of the substance
• Solid


  • Have definite shape and volume
  • Particles are tightly packed together
• Liquid


  • Has definite volume but does not have definite shape
  • Particles are closer to each other
• Gas


  • Highly compressible and feature very large intermolecular distances
  • Particles are far apart, fast-moving and not organized in any way
• Plasma


  • Heating a gas will form a plasma
  • A soup of positively charged particles (ions) and negatively charged particles (electrons)
• Bose-Einstein Condensate


  • A state of matter in which separate atoms or subatomic particles, cooled to near absolute zero (0K)
• Matter is made up of tiny particles
• Particles of matter are moving all the time
• These particles have spaces between them
• The particles of matter attract each other
• Evaporation


  • Liquid to gas
  • A process by which molecules on the surface of the liquid break away and change into gas
• Condensation


  • A process by which water vapor is changed into liquid water
  • Responsible for the formation of clouds
• Melting


  • A physical process that results in phase transition of the substance from a solid to a liquid
  • Affected by the heat energy
• Freezing


  A phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point
• Sublimation


  Conversion of a substance from the solid to the gaseous state without its becoming liquid
• Deposition


  • When a substance in gas form changes states to become a solid
  • The gaseous substance gets deposited bypassing the intermediate liquid state
• Easy Physical Changes


  • Melting - Solid to Liquid
  • Freezing - Liquid to Solid
  • Evaporation - Liquid to Gas
  • Condensation - Gas to Liquid
  • Sublimation - Solid to Gas
  • Deposition - Gas to Solid
• Proton


  • Determining the identity of an atom
  • Determine the atomic number of an element
• Electron


  • Chemical bonding
  • Found in all atoms
  • Acting as the primary carrier of electricity in solids
• Ernest Rutherford


  • Proved that the nucleus of the hydrogen atom (i.e. a proton) is present in the nuclei of all other atoms in the year 1917
• J.J. Thomson


  • Discovered electron
  • The cathode ray tube
  • Cathode ray tube is made up of two electrodes: cathode and anode
• Robert Millikan


  • Oil-drop experiment
  • Calculated the mass of electrons
  • Charge= -1.60x10^-19 C
  • Charge/mass=-1.70x10^8 C/g
• Neutron


  • Stabilizes the atomic nucleus
  • Has a mass nearly equal to that of the proton
  • Present in all known atomic nuclei except the hydrogen nucleus
• Sir James Chadwick


  • Fired alpha radiation at beryllium sheet from a polonium source, leading to the production of an uncharged, penetrating radiation
• Nucleons


  • Either neutron or proton
  • Considered in its role as a component of an atomic nucleus
  • The number of nucleons in an atom determines the atomic mass of an atom
• Solid Sphere Model (Dalton's Atomic Theory)

  • Matter is composed of tiny, indivisible spheres called atoms
  • Atoms of the same element are identical, but atoms of one element are different from those other elements
  • Atoms cannot be created nor destroyed during a chemical change rather, they are rearranged to form a new compounds
  • Atoms of different elements combine in simple whole number ratios to form compounds