Name: ______________________________
Date: _______________________________
Flynt - ___ Period
___th Grade Science
1)
2)
3)
4)
Write the symbol for each of the following elements and then classify each of the
following elements as an alkali metal, an alkaline-earth metal, transition metal,
metalloid, non-metal, halogen, and/or noble gas based on its position in the periodic
table:

chlorine
__Cl Halogen/Non-Metal___________________

boron
__B Metalloid____________________________

lead
__Pb Carbon Family/Post Transition Metal/Metal

calcium
__Ca Alkali-Earth Metal____________________

potassium
__K Alkali Metal__________________________

xenon
__Xe Nobel Gas/Non-Metal_________________

molybdenum __Mo Transition Metal_____________________
How many valence electrons do each of the following elements have?

silicon __4____

boron__3____

tin __4____

potassium _1_____

krypton __8____

cesium __1____

lead _4_____

iodine __7____
Which of the following ions are likely to be formed? (Use a  or an X)

K+__ ____

O3-__X____

P+5 __X____

Al+3 __ ____

Ne+ __X____

N-3 __ ____

Cl __ ____

Ca+2 __ ____
Explain why chlorine is a fairly reactive element while argon is not, even though they are
next to each other in the same period.
Chlorine, a halogen, has 7 valence electrons, while argon, a noble gas, has 8 valence electrons.
According to the Octet Rule, chlorine needs to gain 1 electron in order to achieve a stable electron
configuration. Chlorine can obtain the extra valence electron by forming chemical bonds with other atoms
in order to obtain a stable electron configuration. Argon has a full outer shell of electrons (it has 8 valence
electrons, satisfying the octet rule), so there’s no particular reason for argon to form chemical compounds.
5)
Explain why fluorine and chlorine have similar reactivities. (The word “valence” should be
somewhere in your answer!)
As members of the Halogen Group, both fluorine and chlorine have the same number of valence
electrons (seven). Since valence electrons determine how an element will react chemically with other
elements (chemical reactivity), having the same number of valence electrons gives fluorine and chlorine
similar reactivities. Both elements need one additional electron to meet the Octet Rule and achieve a stable
electron configuration. Therefore both chlorine and fluorine tend to bond with elements that readily provide
the needed extra electron (elements with low electron affinities and low ionization energies).
6)
Explain why magnesium tends to lose electrons when becoming an ion, while sulfur tends
to gain electrons.
With two valence electrons, it’s easier for magnesium to lose its two valence electrons rather than gain
six additional electrons in order to meet the octet rule and achieve a stable electron configuration (thus
becoming like the nearest noble gas). This is why magnesium has an oxidation number of 2+, indicating
that it tends to become a cation with a 2+ charge. In contrast, sulfur—with its six valence electrons—can
most easily meet the octet rule by gaining 2 additional electrons rather than by losing its 6 valence electrons.
Thus, sulfur’s oxidation number is 2-, indicating it typically becomes an anion with a 2- charge.
7)
Research and describe at least 5 unique traits/characteristics of ions, ionic bonds, and
ionic compounds.
From Hyperphysics.com: An ionic bond forms when one or more electrons from one atom are removed
and attached to another atom, resulting in positive and negative ions which attract each other. In chemical
bonds, atoms can either transfer or share their valence electrons. In the extreme case where one or more atoms
lose electrons and other atoms gain them in order to produce a noble gas electron configuration, the bond is
called an ionic bond. Ionic bonds often form between the alkalis and the halides, such as sodium chloride,
NaCl.
From VisionLearning.com:
In ionic bonding, electrons are completely transferred from one
atom to another. In the process of either losing or gaining negatively
charged electrons, the reacting atoms form ions. The oppositely charged
ions are then attracted to each other by electrostatic forces, which are
the basis of the ionic bond.
For example, during the reaction of sodium with chlorine (in the
picture at left), sodium (grey atomic model) loses its one valence
electron to chlorine (green atomic model). In the picture below right, you
can see that this electron exchange results in a positively charged sodium
ion and a negatively charged chlorine ion.
Notice that when sodium loses its one valence electron it gets smaller in size, while chlorine grows larger
when it gains an additional valence electron. This is typical of the relative sizes of ions to atoms. Positive ions
tend to be smaller than their parent atoms while negative ions tend to be larger than their parent. After the
reaction takes place, the charged Na+ and Cl- ions are held together by electrostatic forces, thus forming an
ionic bond. Ionic compounds share many features in common:
 Ionic bonds form between metals and nonmetals.
 In naming simple ionic compounds, the metal is always first, the nonmetal second (e.g., sodium
chloride).
 Ionic compounds dissolve easily in water and other polar solvents.
 In solution, ionic compounds easily conduct electricity.
 Ionic compounds tend to form crystalline solids with high melting temperatures.
From Wikipedia: An ionic bond is a type of chemical bond formed through an electrostatic attraction
between two oppositely charged ions. Ionic bonds are formed between a cation, which is usually a metal, and
an anion, which is usually a nonmetal. Pure ionic bonding cannot exist: all ionic compounds have some degree
of covalent bonding. Thus, an ionic bond is considered a bond where the ionic character is greater than the
covalent character. The larger the difference in electronegativity between the two atoms involved in the bond,
the more ionic (polar) the bond is. Bonds with partially ionic and partially covalent character are called polar
covalent bonds. Ionic bonding is a form of non-covalent bonding. Ionic compounds conduct electricity when
molten or in solution, but not as a solid. They generally have a high melting point and tend to be soluble in
water.
8)
Pick two elements that might be likely to form an ionic bond. Use the number of valence
electrons to explain why you think these two elements might form an ionic bond.
Answers may vary.
Ionic bonds occur between metals and non-metals on the periodic table.
1) For example, consider Na and Cl.
Sodium would lose its lone valence electron and become positively charged and the chlorine would gain
one electron to fill its valence shell, becoming negatively charged.
The positive/negative charge attraction would hold the two ions together.
2) Another example, magnesium and oxygen.
The magnesium would lose its two valence electrons, becoming +2 charged and the oxygen would gain the
two electrons to fill its valence shell, becoming -2 charged in the process.
The positive/negative charge attraction (this time +2/-2, four times as much as the +1/-1 of NaCl) would
hold the two ions together.
3) Last example, Mg and Cl.
The magnesium would lose two electrons, becoming +2 charged and two chlorines (not one) would each
gain one electron, each becoming -1 charged in the process.
The three ions would adhere (bond) to each other by the positive/negative attraction between the ions.