chemistry

• What model represents the three states of matter?

  Particle model
• What does the particle model explain?

  Properties of substances in different states
• What can the particle model also explain?

  Changes of state
• What happens to particles during melting, evaporation, and boiling?

  • Particles gain energy
  • Move apart in melting
  • Become gas in evaporation
  • Form bubbles in boiling
• What are some methods to separate mixtures?

  Filtration, crystallisation, distillation, chromatography
• What determines the method chosen for separation?

  The type of mixture
• What does the term 'separation and purification' refer to?

  Methods to separate mixtures
• Why is it important to understand the particle model?

  It helps explain physical properties and changes
• How does the particle model relate to changes of state?

  It illustrates how particles behave during changes
• What do atoms consist of?

  A nucleus with protons and neutrons
• How can the numbers of particles in an atom be calculated?

  From its atomic number and mass number
• What is Dalton's model of the atom?

  • Atoms are tiny solid balls
  • Atoms cannot be broken down
  • Atoms of a given element are identical
  • Atoms of different elements are different
  • Atoms rearrange during chemical reactions
• What did Dalton believe about the smallest part of an element?

  It is called an atom
• When did John Dalton publish his ideas about atoms?

  In 1803
• What are subatomic particles?

  Objects found in atoms, like protons
• What are the three types of subatomic particles?

  Protons, neutrons, and electrons
• What is the charge of a proton?

  Positive charge
• What is the charge of a neutron?

  No charge
• What is the charge of an electron?

  Negative charge
• How do atoms of different elements differ?

  They have different numbers of protons
• What did Dalton's model lack due to technology limitations?

  Detailed structure of atoms
• What is the timeline of atomic discoveries?

  • 1897: Electrons discovered
  • 1909-1911: Nucleus with electrons
  • 1913: Electrons occupy shells
  • 1918: Protons discovered
  • 1932: Neutrons discovered
• What is the relative mass of a proton?

  1
• What is the relative mass of a neutron?

  1
• What is the relative mass of an electron?

  Negligible mass
• How do the numbers of protons and electrons relate in an atom of an element?

  They are identical in number
• Can atoms of an element have different numbers of neutrons?

  Yes, they can
• What is the significance of Dalton's model in atomic theory?

  It laid the foundation for modern atomic theory
• Who published the first periodic table of elements?

  Dmitri Mendeleev
• What was Mendeleev's goal in organizing elements?

  To find ways to organize known elements
• In what year did Mendeleev publish his periodic table?

  1869
• How are elements arranged in the modern periodic table?

  By atomic number in periods and groups
• What do electronic configurations model?

  How electrons are arranged in atoms
• What is a substance made of one type of atom called?

  Element
• What does relative atomic mass represent?

  The mean mass of an element's isotopes
• What are chemical properties?

  How a substance reacts with others
• What is a compound?

  A substance formed by chemical union
• What is a periodic trend?

  A pattern in properties of elements
• How did Mendeleev classify elements in his table?

  By putting similar properties in groups
• Why did Mendeleev leave gaps in his table?

  For undiscovered elements at the time