Atomic structure

• 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 an element are identical
  • Atoms of different elements are different
  • Atoms rearrange during chemical reactions
• When did John Dalton publish his ideas about atoms?

  In 1803
• What are subatomic particles?

  Objects found in atoms, like protons
• What did Dalton believe about the atoms of a given element?

  They are identical to each other
• What happens to atoms during chemical reactions according to Dalton's model?

  They rearrange to make different substances
• What are the three smaller particles that atoms can be broken down into?

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

  Positive charge
• What is the relative mass of a neutron?

  1 relative to a proton
• What is the charge of an electron?

  Negative charge
• How do atoms of an element compare in terms of protons and electrons?

  They have identical numbers of protons and electrons
• How do atoms of different elements differ?

  They have different numbers of protons and electrons
• Why did Dalton's model change over time?

  Due to the discovery of subatomic particles
• What was discovered in 1897?

  Electrons
• What was discovered between 1909 and 1911?

  Atoms have a nucleus with electrons around it
• What was discovered in 1913?

  Electrons occupy shells (energy levels)
• What was discovered in 1918?

  Protons
• What was discovered in 1932?

  Neutrons
• What do we now know about the structure of atoms?

  They can be broken down into three smaller particles
• How did the discoveries about atoms change our understanding of them?

  We learned about their subatomic structure
• What do atoms consist of?

  A nucleus and electrons in shells
• How can the numbers of particles in an atom be calculated?

  From its atomic number and mass number
• What is the smallest part of an element that can exist?

  • An atom
• What is the central part of an atom called?

  Nucleus
• What does the nucleus contain?

  Protons and neutrons
• What is the mass of the nucleus compared to the atom?

  It has most of the mass of the atom
• What is the plural of nucleus?

  Nuclei
• What is an electron?

  A subatomic particle with a negative charge
• How are electrons arranged in an atom?

  In areas called shells
• How does the size of a nucleus compare to an atom?

  The nucleus is very small compared to the atom
• What are subatomic particles?

  Objects found in atoms, like protons and neutrons
• What is a proton?

  A subatomic particle with a positive charge
• What is the relative mass of a proton?

  1
• What is the relative charge of a proton?

  +1
• What is a neutron?

  An uncharged subatomic particle
• What is the relative mass of a neutron?

  1
• What is the relative charge of a neutron?

  0
• What is the mass of an electron compared to protons and neutrons?

  Very small
• Where is most of the mass of an atom concentrated?

  In its nucleus