CHEMISTRY 🥼🧪

• What is the main component of rock salt?

  Rock salt is a mixture of salt and sand.
• Why can salt dissolve in water while sand cannot?

  Salt can dissolve in water, but sand cannot dissolve.
• What is the process to separate salt from sand using water?

  1. Mix salt and sand with water.
  2. Stir the mixture.
  3. Filter the mixture to collect sand as residue.
  4. Evaporate the water to obtain dry salt crystals.
• What is the charge of protons?

  Protons have a charge of +1.
• What is the role of the nucleus in an atom?

  The nucleus contains protons and neutrons and is positively charged.
• What is the first step in the process of forming salt from water?

  Evaporate the water from the salt.
• How does heating the solution help in the process of forming salt?

  Heating the solution can help dissolve the salt.
• What are the shells in an atom also referred to as?

  • Energy levels
  • Electrons occupy these shells
• Which energy levels are filled first in an atom?

  The lowest energy levels are always filled first.
• How many electrons can each shell hold?


  • 1st shell: 2 electrons
  • 2nd shell: 8 electrons
  • 3rd shell: 8 electrons
• Why are atoms more stable when they have full electronic shells?

  Atoms are more stable when they have full electronic shells.
• What group do elements with 2 electrons in their outer shell belong to?

  Group 2.
• What happens when metals form ions?

  They lose electrons from their outer shell to form positive ions.
• What happens when non-metals form ions?


  They gain electrons from their outer shell to form negative ions.
• Where are non-metals located on the periodic table?

  • Non-metals are on the far right and the top of the periodic table.
• Why is it easier for metals to form positive ions compared to non-metals?

  Not much energy is needed to remove the electrons from metals.
• What are the general properties of metals due to metallic bonding?

  • Strong and hard to break
  • Malleable (can be bent/hammered into different shapes)
  • Good conductors of heat and electricity
  • High melting and boiling points
• How do non-metals differ from metals in terms of physical properties?

  Non-metals are dull looking, more brittle, and aren't always solid.
• What are transition metals known for?

  Transition metals can have more than one ion and are often colored.
• What is the significance of Dmitri Mendeleev's work on the periodic table?

  Mendeleev left gaps for undiscovered elements and predicted their properties.
• What was the arrangement of elements in the early 1800s?

  Elements were arranged by atomic weight.
• What was a limitation of the early periodic table?

  Some elements were placed in the wrong group due to atomic weight arrangement.
• What does the group number in the periodic table indicate?

  The group number tells you how many electrons are on the outer shell.
• How do elements in Group 1 behave in terms of reactivity?

  Elements in Group 1 react more vigorously as you go down the group.
• What are the properties of alkali metals in Group 1?

  • Very reactive
  • Soft and have low density
  • Form +1 ions
  • React vigorously with water and chlorine
  • Reactivity increases as you go down the group
• What is the boiling point trend among noble gases as you go down the group?

  The boiling point increases as you go down the group.
• If neon is a gas at 25 °C, what state is helium at this temperature?

  Helium is also a gas at 25 °C.
• Predict the boiling point of xenon if radon and krypton have boiling points of -62 °C and -153 °C respectively.

  Xenon's boiling point is about -108 °C.
• What is the process of simple distillation?

  1. Heat the solution.
  2. The part with the lowest boiling point evaporates first.
  3. The vapor cools, condenses, and is collected.
  4. The rest of the solution remains in the flask.
  5. Used to obtain pure water from seawater.
• What is a limitation of simple distillation?

  It can only separate substances with very different boiling points.
• What is fractional distillation used for?

  • To separate a mixture of liquids with similar boiling points.
  • Involves heating the mixture and using a fractionating column.
• What happens during fractional distillation when the temperature matches the boiling point of a liquid?

  The liquid with the lowest boiling point evaporates first and reaches the top of the column.
• What is the role of the fractionating column in fractional distillation?

  The column is cooler towards the top, allowing higher boiling point liquids to condense and run back down.
• What are the key steps in Rutherford's experiment?

  1. Conducted by Hans Geiger and Ernest Marsden in 1909.
  2. Concluded that most of the atom is empty space.
  3. Discovered a small, dense, positively charged nucleus.
• What was J.J. Thomson's contribution to atomic theory?

  • Discovered negatively charged particles (electrons).
  • Proposed the plum pudding model of the atom.
• Elements are now ordered in increasing atomic (proton) number
• The top number of an atom shows the relative atomic mass
• The bottom number of an element shows the atomic number
• The vertical collums in a period table are called groups
• Atoms are more stable if they have a full electronic shell