Chp. 2 Vocab

Question 1

atomic mass unit (amu)

Answer 1

A measure of atomic mass; 1/12 of the

mass of an atom of C12.

Question 2

atomic number (Z)

Answer 2

For a chemical element, the number of

protons within the atomic nucleus.

Question 3

atomic weight (A)

Answer 3

The weighted average of the atomic masses
of an atom’s naturally occurring isotopes. It may be expressed
in terms of atomic mass units (on an atomic basis), or the mass
per mole of atoms.

Question 4

Bohr atomic model

Answer 4

An early atomic model in which electrons

are assumed to revolve around the nucleus in discrete orbitals.

Question 5

bonding energy

Answer 5

The energy required to separate two atoms
that are chemically bonded to each other. It may be expressed
on a per-atom basis or per mole of atoms.

Question 6

coulombic force

Answer 6

A force between charged particles such as
ions; the force is attractive when the particles are of opposite
charge.

Question 7

covalent bond

Answer 7

A primary interatomic bond that is formed by

the sharing of electrons between neighboring atoms.

Question 8

electron configuration

Answer 8

For an atom, the manner in which possible

electron states are filled with electrons.

Question 9

electronegative

Answer 9

For an atom, having a tendency to ACEPT valence

electrons. Also used to describe nonmetallic elements.

Question 10

electron state (level)

Answer 10

One of a set of discrete, quantized energies
that are allowed for electrons. In the atomic case, each
state is specified by four quantum numbers.

Question 11

electropositive

Answer 11

For an atom, having a tendency to RELEASE valence

electrons. Also used to describe metallic elements.

Question 12

ground state

Answer 12

A normally filled electron energy state from

which an electron excitation may occur.

Question 13

hydrogen bond

Answer 13

A strong secondary interatomic bond that exists
between a bound hydrogen atom (its unscreened proton)
and the electrons of adjacent atoms.

Question 14

ionic bond

Answer 14

A coulombic interatomic bond that exists between

two adjacent and oppositely charged ions.

Question 15

isotopes

Answer 15

Atoms of the same element that have different atomic

masses.

Question 16

metallic bond

Answer 16

A primary interatomic bond involving the nondirectional
sharing of nonlocalized valence electrons (“sea of
electrons”) that are mutually shared by all the atoms in the metallic solid.

Question 17

mole

Answer 17

The quantity of a substance corresponding to 6.022x10^23

atoms or molecules.

Question 18

Pauli exclusion principle

Answer 18

For an individual
atom, at most two electrons, which necessarily have opposite
spins, can occupy the same state.

Question 19

periodic table

Answer 19

The arrangement of the chemical elements with
increasing atomic number according to the periodic variation
in electron structure. Nonmetallic elements are positioned at
the far right-hand side of the table.

Question 20

polar molecule

Answer 20

A molecule in which there exists a permanent
electric dipole moment by virtue of the asymmetrical distribution
of positively and negatively charged regions.

Question 21

primary bonds

Answer 21

Interatomic bonds that are relatively strong and
for which bonding energies are relatively large. Primary bonding
types are ionic, covalent, and metallic.

Question 22

quantum mechanics

Answer 22

. A branch of physics that deals with atomic
and subatomic systems; it allows only discrete values of energy.
By contrast, for classical mechanics, continuous energy
values are permissible.

Question 23

quantum numbers

Answer 23

A set of four numbers, the values of which
are used to label possible electron states. Three of the quantum
numbers are integers that specify the size, shape, and
spatial orientation of an electron’s probability density; the
fourth number designates spin orientation.

Question 24

secondary bonds

Answer 24

Interatomic and intermolecular bonds that
are relatively weak and for which bonding energies are
relatively small. Normally, atomic or molecular dipoles are
involved. Examples of secondary bonding types are van der
Waals forces and hydrogen bonding.

Question 25

valence electrons

Answer 25

The electrons in the outermost occupied electron

shell, which participate in interatomic bonding.

Question 26

van der Waals bond

Answer 26

A secondary interatomic bond between
adjacent molecular dipoles that may be permanent or
induced.

Question 27

wave mechanical model

Answer 27

An atomic model in which electrons

are treated as being wavelike.