Chem topic 1

• What are the four main points of Dalton's atomic theory?

  Atoms are tiny, indivisible, same for an element, different for other elements
• What are the three main points about electrons discovered by Thompson?

  Negative charge, deflected by electromagnetic fields, small mass
• What is the current model of the atom?

  ● Protons and neutrons are found in the nucleus

  ● Electrons orbit the nucleus in shells

  ● The nucleus is tiny compared to the total volume of atom

  ● Most of atom’s mass is in the nucleus

  ● Most of the atom is empty space between the nucleus and the electrons
• What is the charge of a proton and an electron?

  Proton = +1, Electron = -1
• Which particle has the same mass as a proton?

  Neutron
• Which two particles make up most of an atom's mass?

  Protons and neutrons
• What does the atomic number show about an element?

  Number of protons in an atom
• How is the mass number calculated?

  Mass number = number of protons + number of neutrons
• How is the number of neutrons calculated?

  Number of neutrons = mass number - atomic number
• What is an isotope?

  Atoms of the same element with different number of neutrons
• Why do different isotopes of the same element react in the same way?

  ● Neutrons have no impact on the chemical reactivity

  ● Reactions involve electrons, isotopes have the same number of electrons in the same arrangement
• What is the definition of relative atomic mass?

  Weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon-12
• What is the definition of relative isotopic mass?

  Mass of an atom of an isotope compared with one twelfth of the mass of an atom of carbon-12
• What is the relative isotopic mass same as?

  Mass number
• What are the two assumptions made when calculating mass number?

  1. Contribution of the electron is neglected
  2. Mass of both proton and neutron is taken as 1.0 u
• How is the relative molecular mass and relative formula mass calculated?

  By adding the relative atomic masses of each of the atoms making up the molecule or the formula
• What are the uses of mass spectrometry?

  ● Identify unknown compounds

  ● Find relative abundance of each isotope of an element

  ● Determine structural information
• What is the m/z value of the M+ ion?

  Value of the last peak - 72
• What does the principal quantum number indicate?

  Shell occupied by the electrons
• What is a shell?

  A group of orbitals with the same principal quantum number
• How many electrons can the 1st shell hold?

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

  8
• How many electrons can the 3rd shell hold?

  18
• How many electrons can the 4th shell hold?

  32
• What is an orbital?

  A region around the nucleus that can hold up to two electrons with opposite spins
• How many electrons can an orbital hold?

  2
• What are the 4 types of orbitals?

  ● s orbital

  ● p orbital

  ● d orbital

  ● f orbital
• What is the shape of a p-orbital?

  Dumb-bell shape
• What is the shape of a s-orbital?

  Spherical
• How many orbitals are found in a S subshell?

  1
• How many orbitals does a P subshell have?

  3
• How many electrons can be held in a S subshell?

  2
• How many electrons can be held in a P subshell?

  6
• How many orbitals are present in a D subshell?

  5
• How many electrons can be held in a D subshell?

  10
• How many orbitals are found in a F subshell?

  7
• How many electrons can fill an F subshell?

  14
• What shape is used to represent electrons in the 'electrons in box' representation?

  Arrows

  
• What letter is used to represent the shell number?

  n
• How would you calculate the relative molecular mass of a molecule made up of two atoms of oxygen and one atom of carbon?

  Relative molecular mass = (2 x relative atomic mass of oxygen) + relative atomic mass of carbon