Chapter 5: Periodic Properties of the Elements

Question 1

alkaline earth metals

Answer 1

Fairly reactive metals in group 2A of the periodic table.

Question 2

atomic radius

Answer 2

A set of averge bonding radii determined from measurements on a large number of elements and compounds.

Question 3

covalent radius (bonding atomic radius)

Answer 3

In nonmetals, one-half the distance between two atoms bonded together, and in metals, one-half the distance between two adjacent atoms in a crystal of the metal.

Question 4

diamagnetic

Answer 4

The state of an atom or ion that contains only paired electrons and is, therefore, slightly repelled by an external magnetic field.

Question 5

electron affinity

Answer 5

The energy change associated with the gaining of an electron by an atom in its gaseous state.

Question 6

electron configuration

Answer 6

A notation that shows the particular orbitals that are occupied by electrons in an atom.

Question 7

family (or group) of elements

Answer 7

One of the columns within the main group elements in the periodic table that contain elements that exhibit similar chemical properties.

Question 8

effective nuclear charge (Z_eff)

Answer 8

The actual nuclear charge experienced by an electron, defined as the charge of the nucleus plus the charge of the shielding electrons.

Question 9

ground state

Answer 9

The lowest energy state of an atom or molecule.

Question 10

halogens

Answer 10

One of the highly reactive nonmetals in group 7A of the periodic table.

Question 11

degenerate

Answer 11

Describes two or more electron orbitals with the same value of n that have the same energy.

Question 12

ionization energy

Answer 12

The energy required to remove an electron from an atom or ion in its gaseous state.

Question 13

core electrons

Answer 13

Those electrons in a complete principal energy level and those in complete d and f sublevels.

Question 14

main-group elements

Answer 14

One of the elements found in the s or p blocks of the periodic table, whose properties tend to be predictable based on their position in the table.

Question 15

metalloids

Answer 15

A member of a category of elements found on the boundary between the metals and nonmetals of the periodic table, with properties intermediate between those of both groups; metalloids are also called semimetals.

Question 16

Coulomb’s law

Answer 16

The law that states that the potential energy (E) of two charged particles depends on their charges (q₁ and q₂) and on their separation (r): E = (1/(4πε₀))/((q₁q₂)/r)

Question 17

noble gases

Answer 17

One of the group 8A elements, which are largely unreactive (inert) due to their stable filled p orbitals.

Question 18

nonmetals

Answer 18

A member of a class of elements that tend to be poor conductors of heat and electricity and usually gain electrons during chemical reactions.

Question 19

Hund’s rule

Answer 19

The principle stating that when electrons fill degenerate orbitals, they first fill them singly with parellel spins.

Question 20

orbital diagram

Answer 20

A diagram that gives information similar to an electron configuration but symbolizes an electron as an arrow in a box representing an orbital, with the arrow’s direction denoting the electron’s spin.

Question 21

paramagnetic

Answer 21

The state of an atom or ion that contains unpaired electrons and is, therefore, attracted by an external magnetic field.

Question 22

aufbau principle

Answer 22

The principle that indicates the pattern of orbital fillingin an atom.

Question 23

Pauli exclusion principle

Answer 23

The principle that no two electrons in an atom can have the same four quantum numbers.

Question 24

penetration

Answer 24

The phenomenon of some higher-lever atomic orbitals having significant amounts of probability within the space occupied by orbitals of lower energy level. For example, the 2s orbital penetrates into the 1s orbital.

Question 25

periodic law

Answer 25

A law based on the observation that when the elements are arranged in order of increasing mass, certain sets of properties recur periodically.

Question 26

metals

Answer 26

A member of large class of elements that are generally good conductors of heat and electricity, are malleable, ductile, and lustrous, and tend to lose electrons during chemical changes.

Question 27

periodic property

Answer 27

A property of an element that is predictable based on an element’s position in the periodic table.

Question 28

semiconductors

Answer 28

A material with intermediate electrical conductivity that can be changed and controlled.

Question 29

shielding

Answer 29

The effect on an electron of repulsion by electrons in lower-energry orbitals that screen it from the full effects of nuclear charge.

Question 30

alkali metals

Answer 30

Highly reactive metals in group 1A of the periodic table.

Question 31

transition elements (or transition metals)

Answer 31

One of the elements found in the d block of the periodic table whose properties tend to be less predictable based simply on their position in the table.

Question 32

valence electrons

Answer 32

The electrons that are important in chemical bonding. For main-group elements, the valence electrons are those in the outermost principal energy level.

Question 33

van der Waals radius (nonbonding atomic radius)

Answer 33

One-half the distance between the centers of adjacent, nonbonding atoms in a crystal.