topic 1

• What are the smallest parts of an element that can exist?

  Atoms
• What is the radius of an atom?

  0.1 nanometres
• What do compounds contain?

  Two or more elements
• How are compounds formed?

  By chemical reactions
• What remains unchanged in a mixture?

  Chemical properties of components
• What is an isotope?

  Same number of protons, different neutrons
• How is relative atomic mass calculated?

  Using masses and abundances of isotopes
• What was initially believed about atoms?

  They were tiny undividable spheres
• What did the alpha particle scattering experiment lead to?

  The nuclear model of the atom
• What did Bohr suggest about electrons?

  They orbit in shells
• Who discovered protons and neutrons?

  James Chadwick
• Where do electrons occupy in an atom?

  Lowest energy levels
• What are the maximum electrons for the first three shells?

  • First shell: 2
  • Second shell: 8
  • Third shell: 8
• What is the relative mass of protons?

  1
• What is the relative mass of neutrons?

  1
• What is the relative mass of electrons?

  Very small
• What is the mass number of an atom?

  Sum of protons and neutrons
• What does an atom have in terms of charge?

  No overall charge
• What is the atomic number of an atom?

  Number of protons in an atom
• What are the methods of separation in mixtures?

  • Filtration
  • Crystallisation
  • Distillation
  • Chromatography
  • Simple distillation
  • Fractional distillation
• Describe the atomic models in order of development.

  1. Tiny undividable spheres
  2. Plum pudding model
  3. Nuclear model
  4. Bohr model
• What is the configuration of nitrogen in terms of electrons?

  2, 5

  
• What is the charge of protons?

  Positively charged
• What is the charge of electrons?

  Negatively charged
• What is the charge of neutrons?

  Neutral charge
• What fills first in electron configurations?

  Inner shells
• What is the structure of the atom according to the nuclear model?

  Tiny positive nucleus at the center
• What is the cloud of electrons in an atom?

  Electrons surrounding the nucleus
• How were the initial periodic tables ordered?

  By atomic weight
• What significant discovery was made after Mendeleev's time?

  Isotopes were discovered
• What did Mendeleev do regarding undiscovered elements?

  Left gaps in the periodic table
• Why didn't Mendeleev strictly follow atomic mass?

  Different atomic masses were present
• How is the position of an element in the periodic table used?

  To predict its reactivity
• What does each period in the periodic table represent?

  A new shell of electrons
• What does the group number indicate?

  Number of outer shell electrons
• How does Group 1 behave in terms of reactivity?

  Reacts more violently down the group
• What is the characteristic of Group 0 elements?

  They are unreactive
• What happens to boiling points in Group 0 as you go down the group?

  Boiling point increases down the group
• What is a defining feature of alkali metals?

  One electron in outer shell
• How do alkali metals typically react with water?

  They form ionic compounds