Periodic Table Part 2 Flashcards
What is the prime experimental evidence that led to the theory that electrons are only found in discrete energy levels in the atom?
The observation and analysis of light spectra
What is the ground state?
An atom in which the electrons occupy the lowest possible energy levels
What is the excited state?
An atom in which the electrons occupy higher energy levels than the lowest possible energy levels
How are electron shells filled?
From lowest to highest energy levels
What does the Pauli Exclusion Principle state?
An orbital can contain a maximum of two electrons
When are photons or quanta emitted from atoms?
When electrons release energy as they drop back to their ground state
What does the Aufbau principle state?
Electrons fill shells and sub shells with the lowest energies first
Why does the 4s sub shell fill before the 3d sub shell?
It is of a lower energy
In the Bohr model of the atom, how are electrons depicted?
Electrons circle the nucleus in orbits or shells
What is an element’s spectrum the result of?
Energy released by high energy electrons returning to their normal shells
In Bohr’s atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus, what occurs?
Light is emitted
What were the first nine known elements in the early days of civilisation?
Iron, carbon, copper, sulphur, silver, tin, lead, mercury, gold
What was the property that these first nine elements shared?
They were all of a low reactivity
What did Johann Döbereiner observe?
The average masses of the first and third members of triads of elements with similar chemical properties, are very similar to the atomic weight of the second member of the triad
What did Lothar Meyer’s graphs suggest?
As the atomic number of an element with similar chemical properties increases, so does the molar volume at a similar rate
