atomic structure

• What has caused the model for atomic structure to evolve over time?

  Changes in knowledge and scientific understanding
• What did the Plum Pudding Model propose about atomic structure?

  Atoms consist of a sphere of positive charge
• What is the current understanding of atomic structure?

  Atoms have a dense nucleus with orbiting electrons
• What experiment led to the discovery of the electron shell model?

  The Rutherford scattering experiment in 1911
• What particles make up the nucleus of an atom?

  Protons and neutrons
• What charge does the nucleus of an atom have?

  Overall positive charge
• What is the relationship between protons and electrons in a neutral atom?

  They are equal in number
• 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?

  1/1840
• How can the maximum number of orbiting electrons in a shell be calculated?

  Using the formula $2n^2$
• How many electrons can shell 2 hold?

  8 electrons
• What must happen before the next electron shell can hold electrons?

  Each electron shell must fill first
• What does mass number represent?

  The sum of protons and neutrons
• What is atomic number represented by?

  Z
• What does atomic number equal?

  The number of protons in an atom
• If an atom has an atomic number of 7 and a mass number of 14, how many neutrons does it have?


  7 neutrons
• What is relative atomic mass defined as?

  Mean mass of an atom divided by carbon-12 mass

  
• What do isotopes have in common?

  Same atomic number but different neutrons
• How do neutral atoms of isotopes react chemically?

  They react the same way
• What is the effect of different mass numbers on isotopes?

  They have different physical properties
• What is an ion?

  An atom that has lost or gained electrons
• What is mass spectrometry used for?

  To identify different isotopes and relative atomic mass
• What does Time of Flight (TOF) Mass Spectrometry measure?

  The time ions take to reach a detector
• What are the steps of the mass spectrometry process?

  1. Ionisation: Sample vapourised and ionised
  2. Acceleration: Ions accelerated towards detection plate
  3. Ion Drift: Ions deflected by magnetic field
  4. Detection: Ions hit detection plate, producing charge
  5. Analysis: Current values used to produce spectra
• What happens during the ionisation process in mass spectrometry?

  Electrons are removed, creating +1 charged ions
• What is the effect of a 2+ charged ion in mass spectrometry?

  It has a smaller radius path in the magnetic field
• How is relative atomic mass (Ar) calculated using isotopes?

  Using the formula $Ar =$$(10x75) +$$(12x25) / (75 + 25)$
• What does the chlorine spectra produced by mass spectrometry show?

  A characteristic pattern in a 3:1 ratio

  
• What are the types of electron orbitals?

  s, p, d, and f orbitals

  
• How many electrons can an s-orbital hold?

  2 electrons
• How many electrons can a p-orbital hold?

  6 electrons
• How many electrons can a d-orbital hold?

  10 electrons
• In what order are orbitals filled?

  From s to d, increasing energy
• What is the electron configuration of sodium (Na)?

  Na = $1s^2 2s^2 2p^6 3s^1$

  
• What is the significance of electron pairing in orbitals?

  It stabilizes the atom
• What are the three rules for writing electron configurations?

  1. Fill lowest energy orbital first
  2. Same spin fills orbitals first
  3. No more than 2 electrons per orbital