Electromic Structure Flashcards
(28 cards)
What is electronic structure?
The arrangement of electrons in an atom’s energy levels (shells).
How are electrons arranged in shells?
In fixed energy levels around the nucleus.
What is the maximum number of electrons in the first shell?
2 electrons.
What is the maximum number of electrons in the second and third shells?
8 electrons.
What determines the number of shells an atom has?
The total number of electrons in the atom.
How do you determine the number of electrons in an atom?
It equals the atomic number (in a neutral atom).
What is the link between group number and electrons?
Group number = number of electrons in the outer shell.
Example: Group 2 = 2 outer electrons.
What is the link between period number and shells?
Period number = number of electron shells.
Example: Period 3 = 3 shells.
What is the electronic structure of oxygen (atomic number 8)?
2,6
What is the electronic structure of sodium (atomic number 11)?
2,8,1
What is the electronic structure of chlorine (atomic number 17)?
2,8,7
What is the electronic structure of magnesium (atomic number 12)?
2,8,2
What happens to electrons when atoms form ions?
They are lost or gained to form full outer shells.
What is an electron configuration diagram?
A visual model showing how electrons are arranged in shells.
Why do atoms react chemically?
To achieve a full outer shell and become stable.
What type of ions do metals form?
Positive ions (cations) by losing electrons.
What type of ions do non-metals form?
Negative ions (anions) by gaining electrons.
What is a noble gas configuration?
A full outer shell of electrons (very stable).
Why are Group 0 elements unreactive?
They already have full outer shells (noble gas configuration).
What is the rule for how electrons fill shells?
Electrons fill the lowest energy levels (closest to the nucleus) first.
What is the Bohr model of the atom?
A model that shows electrons orbiting the nucleus in energy levels.
What is meant by ‘valence electrons’?
Electrons in the outermost shell.
Why are valence electrons important?
They determine chemical reactivity and bonding.
What is the electronic structure of aluminum (atomic number 13)?
2,8,3
