Atomic Structure Flashcards
Define binding energy.
The energy involved in the formation of a nucleus from free protons and neutrons.
Define principal quantum number.
The number of subshells in each shell.
Define ground state.
When the electrons are in orbitals of lowest available energy level.
Define excited state.
When at least 1 electron absorbs energy and is promoted to a higher energy level.
State the Aufbau Principle.
Electrons always go into an empty orbital with the lowest energy available.
State Hund’s Rule.
Where a number of orbitals of equal energy are available, electrons occupy them singly first before any pairing occurs.
State the Pauli Exclusion Principle.
Each orbital can only hold 2 electrons of opposite spin.
Define atomic number.
Number of protons contained in nucleus is same as number of electrons surrounding the nucleus. No 2 elements can have the same atomic number.
Define mass number.
Total number of protons and neutrons in nucleus.
Define nucleons.
A constituent (neutron or proton) of an atomic nucleus.
Define isotopes.
Atoms with the same number of protons but different number of neutrons. Elements with same chemical properties, but different physical properties, such as melting point, density, radioactivity…
Define orbital.
The region of space where there is a high probability of locating electrons.
Define shell.
A group of orbitals with the same principal quantum number n.
Define subshell.
A group of orbitals in the same shell and of the same energy level.
Define period.
Each horizontal row of elements in the periodic table.
