Trends of the Periodic Table
Students must be able to draw conclusions about the
similarities and trends in the properties of elements, with
reference to the periodic table
 classify elements as metal, non-metal, or metalloid and locate them on the
periodic table
Metals - More than three quarters of the known elements are metals. Metals share similar
properties: - good conductors of heat and electricity
- luster
- malleable and ductile
- high densities
- high boiling points and melting points - resist stretching and twisting
- solids at room temperature
Nonmetals
- no luster
- poor conductors
- may be solid, liquid or gas
- low densities
- low melting and boiling points
Metalloids (or Semimetals) - have properties of both metals and nonmetals
Mark the metallic elements as M and the non metallic elements as NM and
the Metalloids as “OI” 
_____ Potassium
_____ Antimony
_____ Sm
_____ Chlorine
_____ Hydrogen
_____ As
_____ Boron
_____ Germanium
_____ O
_____ Mercury
_____ Tellurium
_____ N
_____ Silicon
_____ Carbon
_____ Ca

Identify the families of elements
Group 1: Alkali Metals
- low densities and melting points
- good electrical conductivity
- the most reactive metals
- react with oxygen and moisture in the air
- they will react violently with water and are stored under oil or kerosene - due to their
reactivity, they are not found uncombined in nature
Group 2: Alkaline Earth Metals
- similar to the alkali metals, but less reactive, not required to store under oil - harder than
the alkali metals
Group 17: Halogens
- nonmetals
- do not exist in nature in the uncombined state, but their compounds are common - form
salts with group 1 or 2 metals
Group 18: Noble Gases
- gases at room temperature
- occur in the atmosphere in very small amounts - extremely unreactive
Representative or Main Group Elements
- groups 1,2 and 13 - 18
Transition Metals: Groups 3 - 12
- typical metals - shiny, and good conductors
Inner Transition Metals:
Lanthanides: elements 57 - 70 - typical metals
Actinides: elements 89 - 102
Write 3 elements found in each of the following families:
alkali metals__________________________________________________
alkaline earth metals___________________________________________
halogens_____________________________________________________
noble gases__________________________________________________
transition metals _____________________________________________
 predict the formulae of compounds given the formula of another
compound containing elements in the same families
Write the formula for:
Carbonite ion: _______________
Hypophosphite ion: ______________
Perchromate ion: _______________
Iodate ion: ________________
Calcium Hypoflourite: ____________________
Iron (III) Arsenite: ____________________
Nitric acid: _____________________
Nitrous acid (which contains the Nitrite ion)____________________
Sulphuric acid: ________________
Sulphurous acid: _____________________
The following learning outcomes are covered in the remainder
of this package
 describe trends in properties such as melting point, ionization
energy, atomic radius, chemical reactivity, ion charge, and
conductivity
 describe some properties of the alkali metals, alkaline earth
metals, halogens, noble gases, and transition metals
 predict the characteristics of elements knowing the
characteristics of another element in that family
Trends of the Periodic Table - notes
Note: These are general periodic trends of elements. There are
many exceptions to these general rules.
Review
Period - a row of elements on the periodic table.
Group - a column of elements on the periodic table.
Atomic Radius - Atomic radius is simply the radius of the atom, an
indication of the atom's volume.
Period - atomic radius decreases as you go from left to right across a
period.
Why? Stronger attractive forces in atoms (as you go from left to right)
between the opposite charges in the nucleus and electron cloud cause the atom
to be 'sucked' together a little tighter.
Group - atomic radius increases as you go down a group.
Why? There is a significant jump in the size of the nucleus (protons +
neutrons) each time you move from period to period down a group.
Additionally, new energy levels of elections clouds are added to the atom as you
move from period to period down a group, making the each atom significantly
more massive, both is mass and volume.
Electron Affinity: The amount of energy released when an electron
is added to an atom. When electrons are added close to the nucleus,
there is a greater attraction between the negative electron and the
positive nucleus and electron affinity is higher. Therefore, the
smaller the atom, the higher the electron affinity.
Period - Electron affinity generally increases as we go across a period.
Group - Electron affinity generally decreases as we go down a group.
Exceptions: Noble gases have full s and p orbitals at their highest energy levels. Because
of this stability, they do not gain or lose electrons easily. Noble gases are not included
in this general trend.
Electronegativity - Electronegativity is an atom's 'desire' to grab
another atom's electrons. This trend is very similar to Electron
affinity
Period - electronegativity increases as you go from left to right across a
period.
Why? Elements on the left of the period table have 1 -2 valence
electrons and would rather give those few valence electrons away (to achieve the
octet in a lower energy level) than grab another atom's electrons. As a result,
they have low electronegativity. Elements on the right side of the periodic table
only need a few electrons to complete the octet, so they have strong desire to
grab another atom's electrons.
Group - electronegativity decreases as you go down a group.
Why? Elements near the top of the period table have few electrons to
begin with; every electron is a big deal. They have a stronger desire to acquire
more electrons. Elements near the bottom of the chart have so many electrons
that loosing or acquiring an electron is not as big a deal. This is due to the
shielding affect where electrons in lower energy levels shield the positive charge
of the nucleus from outer electrons resulting in those outer electrons not being
as tightly bound to the atom.
Ionization Energy - Ionization energy is the amount of energy
required to remove the outermost electron. It is closely related to
electronegativity.
Period - ionization energy increases as you go from left to right across a
period.
Why? Elements on the right of the chart want to take others atom's
electron (not given them up) because they are close to achieving the octet. The
means it will require more energy to remove the outer most electron. Elements
on the left of the chart would prefer to give up their electrons so it is easy to
remove them, requiring less energy (low ionization energy).
Group - ionization energy decreases as you go down a group.
Why? The shielding affect makes it easier to remove the outer most
electrons from those atoms that have many electrons (those near the bottom of
the chart).
Reactivity - Reactivity refers to how likely or vigorously an atom is
to react with other substances. This is usually determined by how
easily electrons can be removed (ionization energy) and how badly
they want to take other atom's electrons (electronegativity) because
it is the transfer/interaction of electrons that is the basis of
chemical reactions.
Metals
Period - reactivity decreases as you go from left to right across a
period.
Group - reactivity increases as you go down a group
Why? The farther to the left and down the periodic chart you go, the
easier it is for electrons to be given or taken away, resulting in higher reactivity.
Non-metals
Period - reactivity increases as you go from the left to the right across
a period.
Group - reactivity decreases as you go down the group.
Why? The farther right and up you go on the periodic table, the
higher the electronegativity, resulting in a more vigorous exchange of electrons.
Ionic Radius vs. Atomic Radius
Metals - the atomic radius of a metal is generally larger than the ionic
radius of the same element.
Why? Generally, metals loose electrons to achieve the octet. This creates
a larger positive charge in the nucleus than the negative charge in the electron
cloud, causing the electron cloud to be drawn a little closer to the nucleus as an
ion.
Non-metals - the atomic radius of a non-metal is generally smaller than
the ionic radius of the same element.
Why? Generally, non-metals loose electrons to achieve the octet. This
creates a larger negative charge in the electron cloud than positive charge in the
nucleus, causing the electron cloud to 'puff out' a little bit as an ion.
Melting Point
Metals - the melting point for metals generally decreases as you go down a
group.
Non-metals - the melting point for non-metals generally increases as you
go down a group.
Practice Problems
1. Which of the following elements is the most reactive? a. P b. O c. F d. He
2. Which element has the smallest second ionization energy? a. K b. Mg c. Li d. Na
3. Which of the following elements has the smallest atomic radii?
a. P b. O c. F d. N
4. Which of the following elements has the most negative (greatest) electron affinity?
a. P b. O c. F d. N
5. What is the general formula for the oxides formed by alkaline earth metals?
6. The cation has a radius that is smaller or larger than the atom that it is formed from.
(Circle One)
7. Put the following elements in order of increasing radius.
a. Na, K, Rb b. As, Se, Br c. Rb, Rh, I
8. Put the following elements in order of increasing ionization energy.
a. Na, K, Rb b. As, Se, Br c. Rb, Rh, I
9. Which of the following oxides are ionic? Which are molecular?
a. SO2
b. MgO
c. Li2O
d. P2O5
e. Y2O3
f. N2O
g. XeO3
10. Which of the following has the smallest atomic radius? a. Ba b. Cl c. Ne d. S e. Sn
11. Which lists the following in order of more negative electron affinity:
a. Br < Se < Sb < Rb < F
b. Se < Rb < Sb < Br < F
c. Sb < Br < Rb < Se < F
d. Br < F < Rb < Sb < Se
e. Rb < Sb < Se < Br < F
12. Select the atom from the following with the smallest second ionization energy.
a. Al b. Be c. Li d. Mg e. Na
13. Select the atom from the following with the largest radius
a. Cs b. K c. Li d. Na e. Rb
14. Select the ion from the following with the largest radius.
a. F b. Cl c. Br d. I
15. Select the arrangement that shows atoms in order of decreasing electron affinity.
a. K > Na > Li > H
b. H > Li > Na > K
c. H > K > Li > Na
d. Na > Li > K > H
e. Li > Na > K > H
16. Select the arrangement that shows atoms in order of decreasing ionization energy.
a. Li > Na > K > Rb
b. Rb > K > Na > Li
c. K > Li > Na > Rb
d. Rb > Na > Li > K
e. Na > Li > K > Rb
17. Select the arrangement that shows atoms in order of increasing electronegativity.
a. Br < Se < Sr < In < Fr
b. Fr < Sr < Se < Br < In
c. In < Fr < Sr < Se < Br
d. Fr < Sr < In < Se < Br
e. Se < Br < Se < In < Sr
18. To what family, period, or region of the periodic table does the element Ar belong?
a. Noble gases
b. Transition metals
c. Lanthanide series
d. Actinide series
e. Alkali metals
19. List in order of increasing size:
-2
+
+
-2
a. Cl < S < K < Na < Se
+
+
-
-2
b. Na < K < Cl < S < Se
-2
+
+
c.S <Na <Cl <Se2 <K
-
-2
+
+
-2
-2
d.Cl <Se <K <Na <S
+
+
-2
-2
e.K <Na <Cl <Se <S
20. Select the arrangement that shows atoms in order of increasing electron affinity.
a. Cl < O < C < Li
b. Li < C < O < Cl
c. C < Cl < Li < O
d. O < Li < Cl < C
21. List at least three elements that belong to each of the following periods, groups, or families.
a. Noble gases
b. Transition metals
c. Lanthanide series.
d. Actinide series.
e. Metalloids
22. When an atom forms an anion, the radius is ________ than the atom.
a. Larger
b. Smaller
c. Same size
23. Which of the listed elements is the poorest conductor of both heat and electricity?
a. Al
b. Bi
c. Co
d. Mg
e. P
ANSWERS
M
Antimony
M
Sm
NM Chlorine
NM Hydrogen
OI
As
OI
OI
NM O
Potassium
Boron
OI
Germanium
M Mercury
OI Tellurium
NM N
OI
NM Carbon
M
Silicon
Ca
The metalloids or semimetals are located along the line between the
metals and nonmetals in the periodic table. The metalloids are boron,
silicon, germanium, arsenic, antimony, and tellurium.
Write 3 elements found in each of the following families:
(you can look these answers up for yourself!)
alkali metals, alkaline earth metals, halogens, noble gases, transition metals
Write the formula for:
Carbonite ion: CO2-2
Hypophosphite ion: PO2-3
Perchromate ion: CrO5-2
Iodate ion: IO3-2
Calcium Hypoflourite: Ca(FO) 2
Iron (III) Arsenite: Fe(AsO3) 3
Nitric acid: HNO3
Nitrous acid (which contains the Nitrite ion): HNO2
Sulphuric acid: H2SO4
Sulphurous acid: H2SO3
Practice Problems ANSWERS
1. Which of the following elements is the most reactive?
a. P b. O c. F d. He
2. Which element has the smallest second ionization energy?
a. K b. Mg c. Li d. Be
The second ionization energy of Mg is larger than the first because it always takes more energy to remove
an electron from a positively charged ion than from a neutral atom.
3. Which of the following elements has the smallest atomic radii?
a. P b. O c. F d. N
4. Which of the following elements has the most negative electron affinity?
a. P b. O c. F d. N
5. What is the general formula for the oxides formed by alkaline earth metals. RO 6. The cation has a radius that is smaller or larger than the atom that it is formed from.
(Circle One)
7. Put the following elements in order of increasing radius.
a. Na, K, Rb b. As, Se, Br c. Rb, Rh, I
Na < K < Rb Br < Se < As I < Rh < Rb 8. Put the following elements in order of increasing ionization energy. a. Na, K, Rb
b. As, Se, Br c. Rb, Rh, I
9. Which of the following oxides are ionic? Which are molecular?
a. SO2 Molecular b. MgO Ionic c. Li2O Ionic d. P2O5 Molecular e. Y2O3 Ionic f. N2O Molecular g. XeO3 Molecular 10. Which of the following has the smallest atomic radius? a. Ba
b. Cl
c. Ne d. S e. Sn
11. Which lists the following in order of more negative electron affinity: F, Br, Sb, Rb,
Se a. Br < Se < Sb < Rb < F
b. Se < Rb < Sb < Br < F c. Sb < Br < Rb < Se < F d. Br < F < Rb < Sb < Se e. Rb < Sb < Se < Br < F 12. Select the atom from the following with the smallest second ionization energy. a. Al
b. Be c. Li d. Mg e. Na
13. Select the atom from the following with the largest radius
a. Cs b. K c. Li d. Na e. Rb
14. Select the ion from the following with the largest radius. a. Fb. Cl- c. Br- d. I-­ 15. Select the arrangement that shows atoms in order of decreasing electron affinity. a. K
> Na > Li > H
b. H > Li > Na > K c. H > K > Li > Na d. Na > Li > K > H e. Li > Na > K > H
16. Select the arrangement that shows atoms in order of decreasing first ionization
energy.
a. Li > Na > K > Rb b. Rb > K > Na > Li c. K > Li > Na > Rb d. Rb > Na > Li > K e. Na > Li > K > Rb
17. Select the arrangement that shows atoms in order of increasing electronegativity. a.
Br < Se < Sr < In < Fr
b. Fr < Sr < Se < Br < In c. In < Fr < Sr < Se < Br d. Fr < Sr < In < Se < Br e. Se < Br <
Se < In < Sr
18. To what family, period, or region of the periodic table does the element Ar belong?
a. Noble gases b. Transition metals c. Lanthanide series d. Actinide series
e. Alkali metals
19. List in order of increasing size: K+, Se2-, Cl-, Na+, S2- a. Cl- < S2- < K+ < Na+ <
Se2b. Na+ < K+ < Cl-­ < S2-­ < Se2-­ c.S2- <Na+ <Cl- <Se2- <K+ d.Cl- <Se2- <K+ <Na+ <S2- e.K+ <Na+ <Cl- <Se2- <S220. Select the arrangement that shows atoms in order of increasing electron affinity. a. Cl
< O < C < Li
b. Li < C < O < Cl c. C < Cl < Li < O d. O < Li < Cl < C
21. List at least three elements that belong to each of the following periods, groups, or
families. a. Noble gases- Ne, Ar, Kr, Xe, Rn b. Transition metals- Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Al, Y, Zr, Nb, Mo, etc. c.
Lanthanide series- La, Ce, Pr, Nd, Pm, etc. d. Actinide series- Ac, Th, Pa U, Np, etc. e. Representative elements- B, Si, Ge, As, Sb, Te, At 22. When an atom forms an anion, the radius is ________ than the atom.
a. Larger b. Smaller c. Same size
23. Which of the listed elements is the poorest conductor of both heat and electricity?
a. Al b. Bi c. Co d. Mg e. P – only non metallic one in the list!
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