- The electronic configuration of an atom is notation that describes the orbitals in which the electrons occupy and the total number of electrons in each orbital
-Helps to understand the structure of the periodic table of elements
Energy Level
- is the amount of energy, which an electron in an atom can possess "n" is the number of the energy level
- the energy difference two particular energy levels are called the quantum of energy
Ground State: When all the electrons of an atom are in their lowest possible energy level
Excited State: When one or more of an atoms's electrons are in energy
An orbital is the actually region of space occupied by an electron in a particular energy level
A shell is the set off all orbital having the same n-value
A sub-shell is a set orbital in same level
For a given value of "n", different types of orbitals are possible:
n=1; only the s-type
n=2; s and p- types
n=3; s,p,and d-types
n=4; s,p,d,and f-types
* A maximum of 2 electrons place in one orbital
Writing Electronic configurations for Neutral Atoms
- Always start with lowest energy level first
- Figure out how many electron you have (neutral number= atomic number) then start at the lowest energy level (1s)
- Each electrons has an opposite spin
* the 2 electron in the 2p occupy separate suborbitals and are not paired up
Writing Electronic configurations for ion
Negative ion: Add electrons (equal to the charge) to the last unfilled sub-shell, starting where the neutral atom left off
Positive ion: Start with the neutral configuration, and then remove electrons from the outmost shell first
Core Nation
- The set of electrons for an atom can be divided into two subsets; the core electrons and the outer eletrons
- The core of an atom is the set of electrons with the configuration of the noble gas
- The outer electrons consist of all elections outside of core. Core electrons normally take part in chemical reaction
- Locate the atom and not the noble gas at the end of the row above the element
Predicting the number of Valence Electrons
- are electrons which can take part in chemical reactions
- or are all the electrons in an atom EXCEPT those in CORE AND IN FILLED d OR f -sub-shells
