Periodic table + atomic structure

• How does boiling point, melting point, and molecular mass change down group 7?

  It increases
• What is the mass number of Magnesium?

  24
• How many protons, neutrons, and electrons are in a Fluorine atom?

  9, 10, 9
• What are the word equations for the following reactions?

  • Sodium + water → Sodium hydroxide + hydrogen
  • Lithium + chlorine → Lithium chloride
  • Potassium + oxygen → Potassium oxide
• What is the balanced symbol equation for the reaction of sodium with water?

  2Na + 2H2O → 2NaOH + H2
• What is the balanced symbol equation for the reaction of potassium with oxygen?

  4K + O2 → 2K2O
• How do you calculate the relative atomic mass of Br if it contains 55% Br-79 and 45% Br-81?

  Relative atomic mass = \frac{(55 \times 79) + (45 \times 81)}{100} = 79.9
• What is the plum pudding model of the atom?


  The atom is a ball of positive charge with negative electrons embedded in it.
• Which experiment discounted the plum pudding model?


  Alpha particle scattering.
• What model replaced the plum pudding model?


  The nuclear model.
• Who suggested that electrons orbit the nucleus?


  Niels Bohr.
• Which particles are found in the nucleus?


  Protons and neutrons.
• Where are electrons found in an atom?


  In the shells, orbiting the nucleus.
• How big is an atom?


  Very small, approximately 0.1 nm.
• How big is the nucleus compared to the atom?


  The nucleus is 1/10,000 of the size of the atom.
• What is the center of the atom called?

  Nucleus.
• What is the mass of a proton?


  1.
• What is the mass of a neutron?


  1.
• What is the mass of an electron?


  Very small or approximately 1/2000th of a proton.
• What is the charge on a proton?


  +1.
• What is the charge on a neutron?


  0.
• What is the charge on an electron?


  • 1.
• What does the atomic number represent?


  The number of protons in an atom.
• What does the mass number represent?


  The total number of protons and neutrons in an atom.
• What is an element made up of?


  Only one type of atom.
• What is a compound made up of?


  Two or more elements that are chemically bonded.
• What is a mixture made up of?


  Two or more different types of atoms not chemically joined.
• How can you separate a compound?

  By chemical reactions.
• How can you separate a mixture?

  Filtration, crystallisation, simple distillation, fractional distillation, chromatography.
• How did Newlands and Mendeleev arrange the periodic table?


  By atomic weight.
• Why did Mendeleev leave gaps in his version of the periodic table?


  For undiscovered elements.
• How is the periodic table arranged now?


  By atomic number.
• Why are elements in the same group of the periodic table?


  They have the same number of electrons in their outer shell, so have similar properties.
• Where are the metals located on the periodic table?


  Bottom and left.
• Do metals form positive or negative ions?


  Positive ions.
• Where are the non-metals located on the periodic table?


  Top right.
• Do non-metals form positive or negative ions?


  Negative ions.
• What are the elements in Group 0 called?


  Noble gases.
• Why are the elements in Group 0 unreactive?


  They have a full outer shell.
• What are the elements in Group 7 called?


  Halogens.