Atomic orbitals, electronic configurations and the periodic table Flashcards
(41 cards)
what causes atomic spectra
Atomic spectra are caused by electrons moving between different energy levels
How do we refer to the energy in atoms
quantised energy
What does quantum theory state about energy ad matter in this context
Quantum theory states that matter can only emit or absorb energy in small fixed amounts
When an electron in an atom absorbs a photon of energy… what happens
it moves from a lower energy level to a higher energy level
When the electron drops back down … what happens
energy is emitted
The frequency of the line in the emission spectrum represents what?
the difference in energy between the levels.
NOTE: We call these energy levels shells or sub-shells and in Figure 2.3 the letter n = 1, 2, 3, etc. defines what is known as the principal quantum number.
define ground state as it relates to electrons in an atom
the lowest possible electronic configuration the electrons in an atom can adopt
Define first ionisation energy
the amount of energy required to remove one mole of electrons from one mole of gaseous atoms
Describe principal quantum no. and what it determines
Principal quantum number, symbol n, determines the main energy level. It can have values n = 1, 2, 3, 4, etc. The numbers determine the size and energy of the shell.
Describe angular momentum quantum no. and what it determines
Angular momentum quantum number, symbol ℓ, determines the shape of the sub-shell and is labelled as s, p, d, f. This can have values from zero to ( n -1). The second quantum number is also known as the angular momentum quantum number.
If treated as particles, What does Heisenberg’s uncertainty principle state, about electrons
states that is impossible to state precisely the position and momentum of an electron at the same instant
What is important to note in relation to quantum theory on how electrons act
in a wave particle duality nature
If treated as a wave what can be determined about electron s
If treated as a wave, the movement of an electron round the nucleus can be described mathematically.
rom solutions to these wave equations it is possible to produce what
a statistical picture of the probability of finding electrons within a given region
If a region is of high probability for the location of an electron what is it called
Regions of high probability are called atomic orbitals.
Define atomic orbital
An atomic orbital is the volume in space where the probability of finding an electron is more than 90%
Describe atoms as it relates to electron behaviour, location, and no. of occupied energy levels
Electrons behave as standing (stationary) waves in an atom. These are waves that vibrate
in time but do not move in space. There are different sizes and shapes of standing wave
possible around the nucleus, known as orbitals. Orbitals can hold a maximum of two
electrons.
What is magnetic quantum no. and what does it determine
Magnetic quantum number (also known as magnetic quantum number), symbol mℓ, relates to the orientation in space of the orbital. It is dependent on ℓ because mℓ can take on any whole number value between -ℓ and +ℓ.
If treated as particles, what does Heisenberg’s uncertainty principle state about electrons
It is impossible to state precisely the position and the moment of an electron at the same instant.
If treated as waves, what does Heisenberg’s uncertainty principle state about electrons
The movement of an electron round the nucleus can be described mathematically
What is an atomic orbital
Is the volume in space where the probability of finding an electron is more than 90%
Describe s-orbitals
- Spherical like a ball
- one possible orientation
Describe p orbitals
- 2 lobes, along a single plane
- 3 orientations
