Atomic Structure Flashcards
How are electrons grouped in shells based on their energy?
They are grouped so lower energy electrons are closer to the nucleus - higher shell = more energy.
How are elements arranged in the periodic table?
Elements are arranged in order of increasing size, and grouped based on electron configuration.
What is nuclear notation and how do you write it?
Nuclear notation shows the atomic symbol with the mass number above and the atomic number below, both on the left.
Define atomic number
The number of protonsin the nucleus of an atom, which is characteristic of a chemical element and determines its place in the periodic table.
Define atomic mass
The mass of an atom of a chemical element expressed in atomic mass units. It is approximately equivalent to the number ofprotonsand neutronsin the atom (the mass number) or to the average number allowing for the relative abundancesof different isotopes.
Define ion
An atom or moleculewith a net electric charge due to the loss or gain of one or more electrons.
What is the concept: Atomic Orbitals?
Electron shells have subshells (s, p, d, f), each containing orbitals. Each orbital holds up to 2 electrons. Different subshells have different numbers of orbitals.
How do electrons fill their orbital shell? *
Electrons fill orbitals in order of increasing energy, not always in strict numerical order.
Subshells (s, p, d, f) have different energy levels – meaning they fill up in a specific order.
Electrons fill orbitals based on energy levels – lower energy levels fill first.
Overlapping occurs – some orbitals (like 4s) fill before others (like 3d) even though 4 is a higher number than 3. This happens because of energy differences.
What are the three rules for electron configuration?
Aufbau’s Principle, Pauli’s Principle and Hund’s Rule
What is Aufbau’s Principle?
Electrons fill orbitals starting with lowest energy levels and move towards higher energy levels - like a movie theatre. ELECTRONS ARE LAZY
What is Pauli’s exclusion principle?
No 2 electrons can fill one orbital with the same spin - they must have opposite spins.
What’s Hund’s Rule for degenerate orbitals?
Electrons fill each orbital one at a time before pairing up - to avoid crowding and repulsion like school bus.
What’s a cation?
An ion with a positive charge.
What’s an anion?
An ion with a negative charge.
What are the 2 exceptions to the general pattern elements follow in period 4 and why?
Chromium and Copper - Half-filled (d⁵) and fully filled (d¹⁰) d-subshells are more stable due to lower energy and reduced electron repulsion, so one electron shifts from 4s to 3d.
What is ionization energy, successive ionization energy, and how does it relate to electron configuration?
Ionization energy is the energy required to remove an electron from an atom. Successive ionization energy is the increasing energy needed to remove additional electrons one by one. It increases because fewer electrons mean stronger attraction to the nucleus. A large jump in ionization energy happens when removing core electrons, as they are much more tightly bound.
