1.4 Quantum Mechanical Model ***

Question 1

Bohr model fallacy

Answer 1

• Bohr model → electrons follow a clearly defined circular pathway (orbit) at a fixed distance from the nucleus
• could only be applied to atoms with 1 electron
  
  • did not account for the repulsion between multiple electrons surrounding a nucleus

Question 2

Quantum mechanical model

Answer 2

• electrons are localized within regions of space around the nucleus called orbitals
• we can only describe the probability of finding an electron within an orbital

Question 3

orbital

Answer 3

• a region of electron density around an atom or molecule
• contains no more than 2 electrons of opposite spins

Question 4

Heisenberg uncertainty principle

Answer 4

• it is impossible to know an atom’s location and momentum at exactly the same time
  
  • assess location → momentum must stop
  • assess momentum → position must be changing
    
    • contradiction of conditions due to nature of electrons

Question 5

quantum number (n, l, m_l, m_s)

Answer 5

• set of numbers which can completely describe any electron in an atom
  
  • size, shape and orientation of orbitals
• n → l → m_l → m_s (n determines l, l determines m_l, etc)

Question 6

energy state

Answer 6

the position and energy of an electron described by quantum numbers

Question 7

Pauli exclusion principle

Answer 7

no two electrons in a given atom can have the same set of 4 quantum numbers