atomic structure and electron configuration

• What are the main topics covered in atomic structure and electron configuration?

  • Atomic structure
  • Electron configuration
• What topics will not be included in the atomic structure content?

  • Mass spectrometry
  • Calculations involving relative atomic mass
• What is represented by the two, eight, and one in sodium's electron configuration?

  The number of electrons in each energy level: two in the first level, eight in the second, and one in the third.
• How many electrons does a sodium atom have?

  11 electrons
• What does each ring in an atomic diagram represent?

  Each ring represents an energy level.
• What is the nucleus of an atom made of?

  Protons and neutrons
• What is the order of energy levels in an atom?

  The first energy level is closest to the nucleus, followed by the second, and then the third.
• What determines the relative atomic mass of an element?

  The total number of protons and neutrons in the nucleus
• What is the relative mass of a proton and neutron?

  1
• What is the atomic number of sodium?

  11
• In atoms, what is equal to the atomic number?

  The number of protons, which is also equal to the number of electrons
• What is the relative mass of an electron?

  Approximately zero
• Why is the number of protons equal to the number of electrons in atoms?

  Atoms have zero charge because protons (+1 charge) are equal in number to electrons (-1 charge).
• What are the relative charges of protons, neutrons, and electrons?

  • Protons: +1
  • Neutrons: 0
  • Electrons: -1
• What does the PO model imply about electrons?

  Electrons are static and orbit the nucleus.
• How does the PO model differ from the actual behavior of electrons?

  The PO model assumes electrons orbit statically, while actual electrons can be found anywhere within orbitals.
• What is an orbital and what is the probability of finding an electron within it?

  • Orbital: An area in the atom where an electron is most likely to be found.
  • Probability: There is approximately a 95% chance the electron exists within the orbital area.
• How many electrons can each orbital hold?

  2 electrons
• How many orbitals does each subshell have?

  • S: 1 orbital
  • P: 3 orbitals
  • D: 5 orbitals
• How many total electrons can each subshell hold?

  • S: 2 electrons
  • P: 6 electrons
  • D: 10 electrons
• Why are the subshells split into orbitals?

  Each subshell is further divided into orbitals to accommodate electrons in different regions within the energy level.
• What symbol is used to represent energy shells?

  $n$
• List the first four energy levels and the subshells they contain.

  • First level: S
  • Second level: S, P
  • Third level: S, P, D
  • Fourth level: S, P, D, F
• What is the order of subshells filled in energy levels?

  • First level: $1s$
  • Second level: $2s, 2p$
  • Third level: $3s, 3p$
  • Fourth level: $4s, 3d, 4p$
• What is the electron configuration for sodium $(Na)?$


  $1s^2 2s^2 2p^6 3s^1$
• How does the order of subshells filled relate to the periodic table?

  The order of subshells corresponds to the arrangement of elements into S, P, and D blocks in the periodic table.
• What is the maximum number of electrons an S subshell can hold?

  Two electrons
• What is the maximum number of electrons a P subshell can hold?

  Six electrons
• What does the bus seating rule describe in atomic structure?

  • Electrons fill individual orbitals before doubling up
  • Double occupation of orbitals occurs only after all single fills are complete
  • Filling orbitals follows a specific order, from lower to higher energy levels
• How would you draw the electron configuration for $N$ using the bus seating rule?


  $1s^2 2s^2 2p^3$
• Which subshells are present in the second energy level of an atom?

  2s and 2p
• How many electrons are in each subshell of the electron configuration $1s^2 2s^2 2p^6 3s^1?$


  Two in $1s,$ two in $2s,$ six in $2p,$ and one in $3s$
• What are the electron configurations of oxygen and magnesium?

  • Oxygen: $1s^2 2s^2 2p^4$
  • Magnesium: $1s^2 2s^2 2p^6 3s^2$
• What is the full electron configuration of $Ti?$


  $1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^2$
• Which subshells fill before the $3d$ subshell?


  $4s$
• What are the exceptions to the general electron configuration rules?

  • Chromium: $1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^5$
  • Copper: $1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^{10}$
• Why do chromium and copper deviate from the general electron configuration rules?

  To create a more stable electronic configuration by spreading electrons among multiple orbitals.
• What is the electron configuration of $S?$


  $1s^2 2s^2 2p^6 3s^2 3p^4$
• How does losing electrons affect the electron configuration of an ion?

  Electrons are removed from the outermost shell, resulting in a change to the highest-energy occupied subshell.
• What are the three elements contained in all carbohydrates?

  • Carbon
  • Hydrogen
  • Oxygen