Book: Ch. 8

Question 1

Define: periodic law

Answer 1

The periodic law says that, when arranged by atomic mass, the elements exhibit a periodic recurrence of similar properties.

Question 2

Define: electron configuration

Answer 2

The distribution of electrons within the levels and sublevels of an atom.

Question 3

Define: spin quantum number (m_s)

Answer 3

Corresponding to the two directions of the electron’s magnetic field, this number has two possible values, +1/2 or -1/2.

Question 4

What are the four quantum numbers and the possible values each can take?

Answer 4

Principal: n, positive integers
Angular momentum: l, integers from 0 to n - 1
Magnetic: m_l, integers from -l to 0 to +l
Spin: m_s, +1/2 or -1/2

Question 5

Define: exclusion principle

Answer 5

No two electrons in the same atom can have the same four quantum numbers.

Question 6

Per the exclusion principle, a given atomic orbital can hold a maximum of _____ electrons, which must have opposing spins.

Answer 6

two

Question 7

Define: shielding (or screening)

Answer 7

Electrons shield other electrons to some extent from the nuclear charge, which produces an effective nuclear charge.

Question 8

Define: effective nuclear charge (Z_eff)

Answer 8

The nuclear charge an electron actually experiences.

Question 9

How do shielding and Z_eff relate?

Answer 9

As a result of shielding, effective nuclear charge is lowered. More electrons in one sublevel therefore lead to lower nuclear charge, which in turn makes electrons easier to remove.

Question 10

Define: Hund’s rule

Answer 10

When orbitals of equal energy are available, the electron configuration of lowest energy has the maximum number of unpaired electrons with parallel spins.

Question 11

Define: inner electrons (or core electrons)

Answer 11

The electrons of the lower energy levels starting at n - 1.

Question 12

Define: outer electrons

Answer 12

The electrons of the highest energy level (highest n value).

Question 13

Define: valence electrons

Answer 13

1. For main group elements, just the outer electrons.

2. For transition elements, the outer electrons and the n-1 d electrons.

Question 14

Atomic radius generally [increases or decreases?] down a group and [increases or decreases?] across a period.

Answer 14

1. increases

2. decreases

Question 15

Define: ionization energy (IE)

Answer 15

The energy required for the complete removal of 1 mol of electrons from 1 mol of gaseous atoms or ions.

Question 16

Ionization energy [increases or decreases?] down a group and [increases or decreases?] across a period.

Answer 16

1. decreases

2. increases

Question 17

Define: the aufbau principle

Answer 17

A method for determining the electron config. Start at the beginning of the periodic table and add one proton to the nucleus and one electron to the lowest energy sublevel available and repeat until you get the element in question.

Question 18

Define: electron affinity

Answer 18

Energy accompanying the addition of 1 mol of electrons to 1 mol of gaseous atoms or ions.

Question 19

Define: isoelectronic

Answer 19

Ions with a noble gas configuration

Question 20

Define: pseudo-noble gas configuration

Answer 20

If a metal atom attains the stability of empty ns and np sublevels and a filled inner (n-1)d sublevel. Refers to the (n-1)d^10 configuration.

Question 21

Define: paramagnetism

Answer 21

A species with unpaired electrons exhibit paramagnetism: it is attracted by an external magnetic field.

Question 22

Define: diamagnetism

Answer 22

A species with all of its electrons paired exhibits diamagnetism: it is not attracted (and is slightly repelled) by the magnetic field.

Question 23

What is the relationship between a gaseous atom becoming an ion and ionization energy?

Answer 23

Atom (g) -> ion+ (g) + e-

Delta E = IE_1 > 0

Question 24

Define: ionic radius

Answer 24

Measure of the size of an ion and is obtained from the distance between the nuclei of adjacent ions in a crystalline ionic compound.

Question 25

Ionic size [increases or decreases] down a group, and [increases or decreases] across a period.

Answer 25

increases, increases