paper 1

• What does Dalton's model state about atoms?

  Atoms are solid spheres that cannot be divided
• What did JJ Thompson propose about the atom?

  Atoms are clouds of positive charge with electrons
• What experiment did Rutherford conduct?

  Alpha scattering experiment
• What did Rutherford's experiment reveal about atoms?

  Atoms have a central nucleus with mass
• What is the electron shell model?

  Electrons orbit the nucleus in fixed distances
• What are protons?

  Positively charged particles in the nucleus
• What are neutrons?

  Neutral particles found in the nucleus
• What are electrons?

  Negatively charged particles orbiting the nucleus
• What is the definition of an element?

  A substance made of only one type of atom
• How is an atom represented in the periodic table?

  By a chemical symbol starting with a capital letter
• What is a compound?

  A substance with two or more different elements combined
• How can compounds be separated?

  Only by chemical reactions
• What is a chemical reaction?

  Formation of new substances with energy change
• What is a word equation?

  A representation of a chemical reaction using words
• What is a symbol equation?

  A representation using chemical symbols and formulas
• How do you balance a symbol equation?

  Ensure equal number of each atom on both sides
• What is the relative charge of a proton?

  +1
• What is the relative charge of a neutron?


  0
• What is the relative charge of an electron?

  -1
• 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?

  Approximately 1/2000
• What are isotopes?

  Atoms with same protons but different neutrons
• What is an ion?

  A charged particle from gaining or losing electrons
• How do you represent a bromine ion with a negative charge?

  Br⁻
• How many electrons can the first shell hold?

  2 electrons
• How many electrons can the second shell hold?

  8 electrons
• How many electrons can the third shell hold?

  8 electrons
• What is the mass number?

  Sum of protons and neutrons in an atom
• What is the atomic number?

  Number of protons in an atom
• Why do atoms have no overall charge?

  Protons equal electrons in number
• How do you find the number of neutrons in an atom?

  Mass number minus number of protons
• How do you find the number of electrons in an atom?

  Equal to the number of protons
• How do you find the number of neutrons in an ion?

  Mass number minus number of protons
• What is relative atomic mass?

  Average mass of atoms compared to carbon-12
• Why do some elements have non-integer relative atomic masses?

  Due to the presence of isotopes
• What is the formula to calculate the number of neutrons?

  Mass number minus number of protons
• How many neutrons are in an atom with a mass number of 80 and 35 protons?

  45 neutrons
• How do you determine the number of electrons in an ion?

  Protons plus or minus charge of the ion
• What is the charge of a bromide ion (Br^-)?

  Negative charge