chemistry

• How do scientists categorize the periodic table?


  Into different blocks based on the sub shell of the highest energy electron
• What is the name of the block where the highest energy electron is in an S sub shell?

  S block
• In which block is the highest energy electron found in a P sub shell?

  P block
• What is the highest energy electron configuration in the D block?


  D sub shell
• What is the highest energy electron configuration in the F block?


  F sub shell
• Why is it important to check the electron configuration using the periodic table?


  To confirm that the electron configuration is correct
• What is the electron configuration of silicon, which has 14 electrons?


  1s$^2$ 2s$^2$ 2p$^6$ 3s$^2$ 3p$^2$
• How can the position of silicon in the periodic table help confirm its electron configuration?


  By indicating the number of electrons in each sub shell
• What does the first row of the D block represent in terms of electron configuration?


  The electrons in the D sub shell of the third electron shell
• What is the electron configuration of nickel, which has 28 electrons?


  1s$^2$ 2s$^2$ 2p$^6$ 3s$^2$ 3p$^6$ 4s$^2$ 3d$^8$
• What does the periodic table indicate about the filling of sub shells?

  It shows the order in which the sub shells fill with electrons
• What are the blocks of the periodic table based on the highest energy electron sub shell?


  • S block: Highest energy electron in S sub shell
  • P block: Highest energy electron in P sub shell
  • D block: Highest energy electron in D sub shell
  • F block: Highest energy electron in F sub shell
• What should you be able to calculate by the end of the video?

  The maximum number of electrons in a given electron shell
• What is meant by an atomic orbital in a subshell?


  An atomic orbital is a region around the nucleus that can hold up to two electrons with opposite spins
• What are the shapes of the s and p orbitals?


  The s orbital has a spherical shape, while the p orbitals are shaped like dumbbells
• How many electrons can the first shell hold?


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

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


  Up to 18 electrons
• How many electrons can the fourth shell hold?


  Up to 32 electrons
• What happens to the energy of the shells as you move further from the nucleus?


  The energy of the shells increases
• What is the term used for the number assigned to each shell?

  Principal quantum number
• What is the principal quantum number for the second shell?


  2
• What is the principal quantum number for the fourth shell?


  4
• How do you calculate the maximum number of electrons in a shell?


  The maximum number of electrons is given by the formula $2n^2$
• What is the maximum number of electrons in the first shell using the formula?


  2 electrons
• What is the maximum number of electrons in the second shell using the formula?


  8 electrons
• What is the maximum number of electrons in the third shell using the formula?

  18 electrons
• What is an atomic orbital?


  An atomic orbital is a region around the nucleus that can hold up to two electrons with opposite spins
• What must be true about two electrons in the same orbital?


  They must have opposite spins
• How is an electron viewed at A-level compared to GCSE?


  An electron is considered to be a cloud of negative charge
• What should you be able to define by the end of the video?

  Relative isotopic mass and relative atomic mass
• Why do scientists use relative mass in chemistry?


  Because atoms are extremely small and have tiny masses
• What is the reference isotope used for relative masses in chemistry?

  Carbon-12
• What mass is assigned to carbon-12 in chemistry?


  12
• What are isotopes?


  Atoms of the same element with a different number of neutrons
• What are the relative masses of the two main isotopes of copper?


  63 and 65
• How is relative isotopic mass defined?


  As the mass of an atom of an isotope compared with 1/12 the mass of carbon-12
• How many relative isotopic masses are there for each isotope of an element?


  One relative isotopic mass for each isotope
• What is a key characteristic of relative isotopic mass?


  It is always a whole number
• Does relative isotopic mass have units?


  No, it has no units