102 . T, F
Na donates an electron to become Na+ while Cl picks up an electron to become Cl–.103 . T, T, CE
In a concentrated NaCl solution, AgCl will not dissociate because of the common ion effect
that states that the solubility of one salt is reduced by the presence of another salt having a
common ion.
104 . F, F
Hydrogen and deuterium are different isotopes of the same element. Hydrogen has one
neutron while deuterium has two. Because they correspond to the same element, they have
the same number of protons.
105 . F, T
In the periodic table, atomic radius decreases from left to right as electrons are added one at a
time to the outer electron shell. Therefore, electrons within a shell cannot shield one another
from the attractive pull of protons. Since the number of protons is also increasing, there is a
greater positive charge pulling the electrons in close to the nucleus, reducing the atomic
radius.
106 . T, F
The mass number of an element is equal to the total number of protons and neutrons. The
atomic number is the number of protons. Therefore, an element with an atomic number of X
and a mass number of N has N–X neutrons.
107 . T, T, CE
An example of a first-order reaction is radioactive decay. In first-order reactions, the rate is
proportional to the concentration of one reactant. The half-life (τ1/2) of a reaction is the time
needed for the concentration of a substance to decrease to one half its original value.
108 . T, F
Elements in the same group have the same valence electrons and therefore have similar
chemical properties. Oxygen and sulfur are both in Group VI and have six valence electrons. A
period is a horizontal row in the periodic table; oxygen and sulfur are in different periods.
109 . T, T