Ions

• What are the three main subatomic particles that make up an atom?

  Protons, neutrons, and electrons
• What happens to an atom when it changes the number of neutrons?

  It becomes an isotope
• What occurs when an atom changes the number of electrons?

  It becomes an ion
• What is the charge and relative mass of a proton?

  Positive charge and a relative mass of 1
• What is the central part of an atom called?

  Nucleus
• What is the relationship between protons and electrons in a neutral atom?

  They have the same number
• What is the charge and mass of an electron?

  Negative charge and negligible mass
• What are ions?

  Charged particles formed when an atom gains or loses electrons
• What happens to an atom when it loses one or more electrons?

  It becomes a positively-charged ion
• What happens to an atom when it gains one or more electrons?

  It becomes a negatively-charged ion
• How many electrons does a neutral helium atom have?

  Two electrons
• What is the result of a helium atom losing one electron?

  It becomes a positive ion
• What is the result of a helium atom gaining an electron?

  It becomes a negative ion
• Who revised Rutherford's model of the atom in 1913?

  Niels Bohr
• What did Niels Bohr suggest about electrons in his model?

  Electrons orbit the nucleus in different energy levels
• How does Bohr's model explain the colors of flames in chemical reactions?

  It relates to the pattern of energy released by electrons
• What happens to electrons when atoms absorb energy?

  They are pushed to higher energy levels
• What occurs when excited electrons return to lower energy levels?

  They release light of definite frequencies
• What are the key features of Bohr's model of the atom?

  • Electrons orbit the nucleus in fixed energy levels
  • Energy levels are at specific distances from the nucleus
  • Electrons release light when they return to lower energy levels
• What are the differences between isotopes and ions?

  • Isotopes: Atoms with the same number of protons but different numbers of neutrons
  • Ions: Atoms that have gained or lost electrons, resulting in a charge
• What is the significance of the nucleus in an atom?

  • Contains protons and neutrons
  • Has most of the mass of the atom
  • Central part of the atom
• What is the role of electromagnetic radiation in electron excitation?

  • Atoms absorb energy from electromagnetic radiation
  • Electrons are pushed to higher energy levels
  • Excited electrons eventually release light when returning to lower levels