Ch7 Flashcards
(16 cards)
What is effective nuclear charge (Zeff)?
Zeff = Z - S, where Z is the number of protons and S is the average number of core electrons.
Effective nuclear charge represents the net positive charge experienced by an electron in a multi-electron atom.
How does effective nuclear charge change across a period?
Zeff increases as atomic number increases across a period.
This is due to the increasing nuclear charge while core electrons remain constant.
How does effective nuclear charge change down a group?
Zeff slightly increases as atomic number increases down a group.
Larger core electrons are less effective at shielding the outer electrons from the nuclear charge.
What is the formula for calculating effective nuclear charge?
Zeff = Z - S.
Z represents the number of protons, and S represents the average number of core electrons.
What happens to atomic size as you move across a period?
Atoms become smaller as you move across a period.
The increased nuclear charge leads to a stronger attraction between the nucleus and outermost electrons.
What happens to atomic size as you move down a group?
Atoms become larger as you move down a group.
The principal quantum number (n) increases, leading to greater distance from the nucleus.
What is the relationship between cations and their parent atoms?
Cations are smaller than their parent atoms.
They lose electrons from the most spatially extended orbital.
What is the relationship between anions and their parent atoms?
Anions are larger than their parent atoms.
They gain electrons into the most spatially extended orbital.
What is an isoelectronic series?
A group of ions or atoms that have the same number of electrons.
For example, O2-, F-, Na+, Mg2+, and Al3+ all have 10 electrons.
Which ion in an isoelectronic series is the largest?
O2- is the largest in an isoelectronic series.
As the nuclear charge increases, the size of the ions decreases: O2- > F- > Na+ > Mg2+ > Al3+.
What is the trend for atomic and ionic size in relation to nuclear charge?
As nuclear charge increases, atomic and ionic size decreases.
This is true within an isoelectronic series.
Fill in the blank: The distance between two nuclei in a molecule is called the _______.
Bond Distance
Fill in the blank: The _______ radius is half the bond distance for identical atoms in a molecule.
Covalent
True or False: The size of the s-orbitals increases with the principal quantum number.
True
What is the trend for atomic radius as you move across a period in the periodic table?
Decreases
What is the trend for atomic radius as you move down a group in the periodic table?
Increases
