Ch. 3: “Atoms & the
Periodic Table”
Section 3: “Families of Elements”
1. Classify the following based
on their position on the periodic
table.
a. Fe
 transition metal
b. K
 alkali metal
c. Sr
 alkaline-earth metal
d. Pt
 transition metal
2. Predict whether cesium
+
2+
forms Cs or Cs ions.

Cesium is an alkali metal, so it has one
valence electron that is removed to
form a Cs+ ion.
3. Describe why chemists might sometimes
store reactive chemicals in argon, Ar. To
which family does argon belong?


Reactive chemicals might react with
oxygen or water vapor in the air. They
will not react with argon because it is
inert.
Argon is a noble gas.
4. Determine whether the
following substances are likely
to be metals or nonmetals:
a. a shiny substance used to make flexible bed
springs
 metal
b. a yellow powder from underground mines
 nonmetal
c. a gas that does not react
 nonmetal
d. a conducting material used within flexible
wires
 metal
5. Describe why atoms of bromine,
Br, are so reactive. To which family
does bromine belong?

Bromine, a halogen, is one electron
short of having 8 valence electrons. It
will readily react with an element that
can supply that electron.
6. Predict the charge of a
beryllium ion.

Beryllium is an alkaline-earth metal.
Therefore, it has two valence electrons
that can be removed to form a Be2+
ion.
7. Identify which element is
more reactive: lithium, Li, or
barium, Ba.

Lithium is an alkali metal and is more
reactive than an alkaline-earth metal
such as barium.
8. Critical Thinking: How can you
determine if a metal is an alkali,
alkaline-earth, or transition metal?

Check the reactivity of the metal
against the reactivities of other alkali,
alkaline-earth, and transition metals.
The element belongs to the group that
is most similar to the element
chemically.