Periodic Trends

Question 1

Degenerate orbitals

Answer 1

share the same energy

Question 2

Ionic size depends on:

Answer 2

1. the nuclear charge
2. the number of electrons
3. the orbital in which electrons reside

Question 3

Ions increase:

Answer 3

down a row because of the increasing value of n

Question 4

cations are smaller than their parent atoms because:

Answer 4

the outermost electron is removed and repulsions between electrons are reduced

Question 5

anions are larger than their parent atoms because:

Answer 5

electrons are added and repulsions between electrons are increased

Question 6

Coulomb’s Law

Answer 6

For like charges, the potential charge repels and opposite charges attract

The strength of the repulsion relies on the charge magnitudes and the distance between charges

A greater charge magnitude results in a stronger attraction

Question 7

Effective Nuclear Charge

Answer 7

the total amount of attraction that an electron feels for the nucleus

Question 8

Aufbau’s Principle

Answer 8

Orbitals fill lowest to highest energy

Question 9

Hund’s Rule

Answer 9

For degenerate orbitals, the lowest energy is attained when
the number of electrons with the same spin is maximized.

Or simply, orbitals half fill before they fill

Question 10

Pauli Exclusion Principle

Answer 10

No two electrons in the
same atom can have
exactly the same energy.

No two
electrons in the same
atom can have identical
sets of quantum numbers.

Question 11

bonding atomic radius

Answer 11

one half the distance between covalently bonded nuclei

Question 12

sizes of atoms tend to:

Answer 12

increase from left to right across a row (due to increasing effective nuclear charge)

Question 13

effective nuclear charge

Answer 13

how closely electrons are attracted to the nucleus and how repulsed they are by the other electrons

if electrons are strongly attracted to the nucleus like in n=1, then the effective charge is strong

Question 14

isoelectronic series

Answer 14

ions have the same number of electrons

Ionic size decreases with an increasing nuclear charge.

Question 15

ionization energy

Answer 15

the amount of energy required to remove an electron from the ground state

Question 16

first ionization energy

Answer 16

the amount of energy required to remove the first electron

Question 17

second ionization energy

Answer 17

the amount of energy required to remove the second electron

Question 18

For atoms in the same group, effective nuclear charge is essentially the same BUT

Answer 18

valence
electrons farther from the nucleus are removed more easily

Question 19

Discontinuities in First Ionization Energy

Answer 19

(1) between groups 2A and 3A the energy decreases because the electron is removed from a p
orbital rather than an s orbital.

(2) occurs between groups 5A and 6A because the electron removed comes from a doubly occupied orbital

Question 20

Electron Affinity

Answer 20

energy change accompanying the addition of an electron

Question 21

Electron Affinity becomes more ____ as it goes from left to right across a row

Answer 21

exothermic

Question 22

Metallic Character

Answer 22

has a tendency to form cations and metal oxides to neutralize acids (they act as a base)