Chapter 4 The Periodic Table - PowerPoint PPT Presentation

Slide1 l.jpg
Download
1 / 50

Chapter 4 The Periodic Table. Chapter 4 – The Periodic Table. Section 1 - How Are Elements Organized?. Pure elements at room temperature and atmospheric pressure can be solids, liquids, or gases. Some elements are colorless. Others are colored.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Presentation

Chapter 4 The Periodic Table

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Slide1 l.jpg

Chapter 4

The Periodic Table


Slide2 l.jpg

Chapter 4 – The Periodic Table

Section 1 - How Are Elements Organized?

Pure elements at room temperature and atmospheric pressure can be

solids, liquids, or gases. Some elements are colorless. Others are colored.

Despite the differences between elements, groups of elements share

certain properties.

Similarly, the elements fluorine, chlorine, bromine, and iodine can

combine with sodium in a 1:1 ratio to form NaF, NaCl, NaBr, and NaI.

These compounds are also white solids that can dissolve in water to form

solutions that conduct electricity. These examples show that even though

each element is different, groups of them have much in common.


Slide3 l.jpg

Chapter 4 – The Periodic Table

Section 1 - How Are Elements Organized?

In 1865, the English chemist John Newlands arranged the known

elements according to their properties and in order of increasing atomic

mass. He placed the elements in a table.

In 1869, the Russian chemist Dmitri Mendeleev used Newlands’s observation

and other information to produce the first orderly arrangement, or

periodic table, of all 63 elements known at the time. Mendeleev arranged the

elements in order of increasing atomic mass. Mendeleev started a new row

each time he noticed that the chemical properties of the elements repeated.


Slide4 l.jpg

Chapter 4 – The Periodic Table

Section 1 - How Are Elements Organized?

He placed elements in the new row directly below elements of similar

chemical properties in the preceding row. He arrived at the pattern

shown below.

Two interesting observations can be made about Mendeleev’s table.

First, Mendeleev’s table contains gaps that elements with particular

properties should fill. He predicted the properties of the missing elements.


Slide5 l.jpg

Chapter 4 – The Periodic Table

Section 1 - How Are Elements Organized?

Second, the elements do not always fit neatly in order of atomic mass.

For example, Mendeleev had to switch the order of tellurium, Te, and

iodine, I, to keep similar elements in the same column. At first, he thought

that their atomic masses were wrong. However, careful research by others

showed that they were correct. Mendeleev could not explain why his

order was not always the same.

About 40 years after Mendeleev published his periodic table, an English

chemist named Henry Moseley found a different physical basis for the

arrangement of elements. Moseley realized that the periodic table should be

arranged by atomic number, not atomic mass. When the elements were arranged

by increasing atomic number, the discrepancies in Mendeleev’s table disappeared.


Slide6 l.jpg

Chapter 4 – The Periodic Table

Section 1 - How Are Elements Organized?

The periodic law states that the repeating physical and chemical properties of elements change periodically with their atomic number

To understand why elements with similar properties appear at regular

intervals in the periodic table, you need to examine the electron configurations

of the elements.

Elements in each column of the table have the same number of electrons

in their outer energy level. These electrons are called valence electrons.

A vertical column on the periodic table is called a group or family.

A horizontal row on the periodic table is called a period.


Slide7 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Elements in groups 1, 2, and 13–18 are known as the main group elements.

Four groups within the main-group elements have special names.

These groups are the alkali metals(Group 1), the alkaline-earth metals

(Group 2), the halogens(Group 17), and the noble gases(Group 18).


Slide8 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

The Alkali Metals Make Up Group 1

Alkali metals are so named because they

are metals that react with water to make alkaline

solutions.

All have a single valence electron

Alkali metals are usually stored in oil to keep them from reacting with

the oxygen and water in the air.

Because of their high reactivity,

Alkali metals are never found

in nature as pure elements but

are found combined with other

elements as compounds.


Slide9 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

The Alkaline-Earth Metals Make Up Group 2

Like the alkali metals, the alkaline-earth metals

are highly reactive, so they are usually found as

compounds rather than as pure elements

All have 2 valence electrons

The alkaline-earth metals are not as reactive as alkali metals, however

they are harder and have higher melting points.


Slide10 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

The Halogens make up Group 17

Halogens have 7 valence electrons

The halogens are the most reactive group

of nonmetal elements

The halogens have a wide range of physical properties. Fluorine and

chlorine are gases at room temperature, but bromine, is a liquid, and

iodine and astatine are solids.


Slide11 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

The Noble Gases make up Group 18

The noble gases were once called

inert gasesbecause they were

thought to be completely unreactive.

The low reactivity of noble gases leads to

some special uses. Helium, a noble gas, is used to fill blimps because

it has a low density and is not flammable.

Hydrogen Is in a Class by Itself

Hydrogen is the most common element in the universe. It is estimated that

about three out of every four atoms in the universe are hydrogen. Because

it consists of just one proton and one electron, hydrogen behaves unlike any

other element.


Slide12 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

The Transition metals make up Groups 3 through 12

Unlike the main-group elements, the transition

metals in each group do not have identical

outer electron configurations.

Generally, the transition metals are less reactive

than the alkali metals and the alkaline-earth metals are.

Lanthanides and Actinides

Part of the last two periods of transition metals are placed toward the bottom of the periodic table to keep the table conveniently narrow,

The elements in the first of these rows are called

the Lanthanides because their atomic numbers

follow the element lanthanum.

Likewise, elements in the row below the lanthanides are called

Actinides because they follow actinium.


Slide13 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Summary of properties of selected groups

Group 1 – All have 1 valence electron, and will easily lose this electron

to form 1+ ions

Group 2 – All have 2 valence electrons, and will easily lose both electrons

to form 2+ ions

Group 13 – All have 3 valence electrons, and will easily lose all of them to

Form 3+ ions

Group 16 – all have 6 valence electrons and will easily gain 2 electron to

Form 2- ions

Group 17 – all have 7 valence electrons and will easily gain 1 electron to

Form 1- ions

Group 18 – have a full outer shell with 8 electrons and will not react with

other atom easily.


Slide14 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Transition elements – are able to have multiple ion charges. All

Possible charges are positive due to lose of electrons. Many will

form a colored aqueous solution.


Slide15 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Most elements of the periodic table are called Metals

All metals are excellent conductors of electricity.

Metals are excellent conductors of heat.

Metals are ductile and malleable.

Ductilemeans that the metal can be squeezed out into a wire.

Malleablemeans that the metal can be hammered or

rolled into sheets.

Metals tend to lose electrons to complete the octet rule.

All metals are solid except mercury, which is a liquid.


Slide16 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Most elements of the periodic table near groups

14 -18 are called Nonmetals

All nonmetals are poor conductors of electricity.

Metals are poor conductors of heat.

Solid nonmetals are brittle and break easily

Metals tend to gain electrons to complete the octet rule.

Nonmetals are found in all three states of matter with bromine being the only

liquid.

Metalloids are elements that share properties of both metals and nonmetals

Metalloids are elements B, Si, As, Te, At, Ge, Sb and Po


Slide17 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Review Questions

At STP which element has a definite shape and volume?

1. Ag

2. Hg

3. Ne

4. Xe

Which element is a member of the halogen family?

1. K

2. B

3. I

4. S


Slide18 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Review Questions

The metalloids that are included in Group 15 are antimony (Sb) and

1. N

2. P

3. As

4. Bi

A characteristic of most nonmetallic solids is that they are

1. brittle

2. ductile

3. malleable

4. conductors of electricity

More than two-thirds of the elements of the Periodic Table are classified as

1. metalloids

2. metals

3. nonmetals

4. noble gases


Slide19 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Review Questions

To which group do the alkaline earth metals belong?

1. 1

2. 2

3. 11

4. 12

Which three elements have the most similar chemical properties?

1. Ar, Kr, Br

2. K, Rb, Cs

3. B, C, N

4. O, N, Si

When metals form ions, they tend to do so by

1. losing electrons and forming positive ions

2. losing electrons and forming negative ions

3. gaining electrons and forming positive ions

4. gaining electrons and forming negative ions


Slide20 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Review Questions

The chemical properties of the elements are periodic functions of their atomic

1. masses

2. weights

3. numbers

4. radii

Which halogen is a solid at STP?

1. fluorine

2. chlorine

3. bromine

4. iodine

Which element is in Group 2 and Period 7 of the Periodic Table?

1. magnesium

2. manganese

3. radium

4. radon


Slide21 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Review Questions

An atom in the ground state contains 8 valence electrons. This atom is classified

as a

1. metal

2. semimetal

3. noble gas

4. halogen

Which category is composed of elements that have both positive and negative

charges?

1. the alkali metals

2. the transition metals

3. the halogens

4. the alkaline earths


Slide22 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Review Questions

Which element is so active chemically that it occurs naturally only in compounds?

1. potassium

2. silver

3. copper

4. sulfur

The elements of the Periodic Table are arranged in horizontal rows according to

each successive element's greater

1. atomic mass

2. atomic radius

3. number of protons

4. number of neutrons


Slide23 l.jpg

Chapter 4 – The Periodic Table

Section 2 - Tour of the Periodic Table

Review Questions

In which list are the elements arranged in order of increasing atomic mass?

1. Cl, K, Ar

2. Fe, Co, Ni

3. Te, I, Xe

4. Ne, F, Na

Which Group of the Periodic Table contains atoms with a stable outer electron

configuration?

1. 1

2. 8

3. 16

4. 18

The element in Period 4 and Group 1 of the Periodic Table would be classified as a

1. metal

2. metalloid

3. nonmetal

4. noble gas


Slide24 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

The arrangement of the periodic table reveals trends in the properties of

the elements. A trendis a predictable change in a particular direction.

Metallic Trend

All of the elements of the periodic table increase in metallic

characteristics as they get closer to francium.

This will make group 1 the most metallic group and period 7 the

most metallic period.

Nonmetallic Trend

All of the elements of the periodic table increase in nonmetallic

characteristics as they get closer to flourine.

This will make group 17 the most nonmetallic group and period 2 the

most nonmetallic period.

Note: The noble gases are not considered part of the metallic or nonmetallic trends

due to there resistance to chemical reactions.


Slide25 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Ionization Energy

The energy that is supplied to remove an electron is the ionization energy

of the atom.


Slide26 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Ionization Energy Decreases as You Move Down a Group

Each element has more occupied energy levels than the one above it has. Therefore, the outermost electrons are farthest from the nucleus in elements near the bottom of a group.

Similarly, as you move down a group, each successive element contains

more electrons in the energy levels between the nucleus and the

outermost electrons. These inner electrons shield the outermost electrons

from the full attractive force of the nucleus. This electron shielding causes

the outermost electrons to be held less tightly to the nucleus.


Slide27 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Ionization Energy Increases as You Move Across a Period

From one element to the next in a period, the number of protons and the

number of electrons increase by one each. A higher nuclear charge more

strongly attracts the outer electrons in the same energy level, but the

electron-shielding effect from inner-level electrons remains the same.

Thus, more energy is required to remove an electron because the

attractive force on them is higher.


Slide28 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table


Slide29 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Atomic Radius

The exact size of an atom is hard to determine. An atom’s size depends on

the volume occupied by the electrons around the nucleus, and the electrons

do not move in well-defined paths. Rather, the volume the electrons

occupy is thought of as an electron cloud, with no clear-cut edge. In addition,

the physical and chemical state of an atom can change the size of an

electron cloud.

The diagram belowshows one way to measure the size of an atom. This

Method involves calculating the bond radius, the length that is half the distance

between the nuclei of two bonded atoms. The bond radius can change

slightly depending on what atoms are involved.


Slide30 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Atomic Radius Increases as You Move Down a Group

As you proceed from one element down to the next in a group, another

principal energy level is filled. The addition of another level of electrons

increases the size, or atomic radius, of an atom.

Atomic Radius Decreases as You Move Across a Period

As you move from left to right across a period, each atom has one more

proton and one more electron than the atom before it has. As a result,

electron shielding does not play a role as you move across a period.

Therefore, as the nuclear charge increases across a period, the effective

nuclear charge acting on the outer electrons also increases. This increasing

nuclear charge pulls the outermost electrons closer and closer to the nucleus

and thus reduces the size of the atom.


Slide31 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table


Slide32 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Electronegativity

Atoms often bond to one another to form a compound. These bonds can

involve the sharing of valence electrons. Not all atoms in a compound

share electrons equally. Knowing how strongly each atom attracts bonding

electrons can help explain the physical and chemical properties of the

compound.

Linus Pauling, one of America’s most famous chemists, made a scale

of numerical values that reflect how much an atom in a molecule attracts

electrons, called electronegativity values. Chemical bonding that comes

from a sharing of electrons can be thought of as a tug of war. The atom

with the higher electronegativity will pull on the electrons more strongly

than the other atom will.

Fluorine is the element whose atoms most strongly attract shared

electrons in a compound. Pauling arbitrarily gave fluorine an electronegativity

value of 4.0.Values for the other elements were calculated in relation

to this value.


Slide33 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Electronegativity Decreases as You Move Down a Group

Metals tend to have small electronegativity because they would rather

lose an electron than gain electrons to fulfill the octet rule.

As you go down a group the distance between the valence electrons and

the nucleus increase, weakening the “grip” the nucleus has on it valence

electrons due to electron shielding.

Electronegativity Increases as You Move Across a Period

Nonmetals tend to have large electronegativity because they would rather

gain an electron than lose electrons to fulfill the octet rule.

As you go across a period the distance between the valence electrons and

the nucleus decreases, strengthening the “grip” the nucleus has on it valence

electrons.


Slide34 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table


Slide35 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Periodic Trends in Ionic Size

Recall that atoms form ions by either losing or gaining electrons. Like

atomic size, ionic size has periodic trends. As you proceed down a group,

the outermost electrons in ions are in higher energy levels. Therefore, just

as atomic radius increases as you move down a group, usually the ionic

radius increases as well. These trends hold for both positive and negative ions.

Metals tend to lose one or more electrons and form a positive ion. As

you move across a period, the ionic radii of metal cations tend to decrease

because of the increasing nuclear charge. As you come to the nonmetal

elements in a period, their atoms tend to gain electrons and form negative

ions. The diagram on the next slideshows that as you proceed through

the anions on the right of a period, ionic radii still tend to decrease

because of the anions’ increasing nuclear charge.


Slide36 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Summary of Ionic Radii

Atoms that form anions will increase in ionic radius, due to the

nuclear charge becoming less than the total electron cloud charge.

Atoms that form cations will decrease in ionic radius due to the nuclear

charge becoming greater than the electron cloud charge.

All atoms forming anions or cations will increase ionic radius when

moving down a group because of the addition of a principle energy

level.


Slide37 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Other information about the periodic table.

All elements with an atomic number greater than 83 have isotopes

that are not stable and will undergo nuclear decay. (They are radioactive)

Chemistry Reference tables lists, electronegativity and ionizations energies

and atomic radii.


Slide38 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Which element forms an ion that is larger than its atom?

1. Cl

2. Ca

3. Li

4. Mg

Which atom has a radius larger than the radius of its ion?

1. Cl

2. Ca

3. S

4. Se

Which of the following elements in Period 3 has the greatest metallic character?

1. Ar

2. Si

3. Mg

4. S


Slide39 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Which period of the Periodic Table contains more metallic elements than

nonmetallic elements?

1. Period 1

2. Period 2

3. Period 3

4. Period 4

As the elements in Period 3 are considered from left to right, they tend to

1. lose electrons more readily and increase in metallic character

2. lose electrons more readily and increase in nonmetallic character

3. gain electrons more readily and increase in metallic character

4. gain electrons more readily and increase in nonmetallic character

Compared to the nonmetals in Period 2, the metals in Period 2 generally have larger

1. ionization energies

2. electronegativities

3. atomic radii

4. atomic numbers


Slide40 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Which of the following Group 2 elements has the lowest first ionization energy?

1. Be

2. Mg

3. Ca

4. Ba

Which of the following atoms has the greatest tendency to attract electrons?

1. barium

2. beryllium

3. boron

4. bromine

In which shell are the valence electrons of the elements in Period 2 found?

  1. 1

  2. 2

  3. 3

  4. 4


Slide41 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

Which of the following ions has the smallest radius?

1. F-

2. Cl-

3. K+

4. Ca2+

The ability of carbon to attract electrons is

1. greater than that of nitrogen, but less than that of oxygen

2. less than that of nitrogen, but greater than that of oxygen

3. greater than that of nitrogen and oxygen

4. less than that of nitrogen and oxygen

Which trends appear as the elements in Period 3 are considered from left to right?

1. Metallic character decreases, and electronegativity decreases.

2. Metallic character decreases, and electronegativity increases.

3. Metallic character increases, and electronegativity decreases.

4. Metallic character increases, and electronegativity increases.


Slide42 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

As the atoms in Period 3 of the Periodic Table are considered from left to right,

the atoms generally show

1. an increase in radius and an increase in ionization energy

2. an increase in radius and a decrease in ionization energy

3. a decrease in radius and an increase in ionization energy

4. a decrease in radius and a decrease in ionization energy

Which Group 16 element has only unstable isotopes?

1. Po

2. Te

3. Se

4. S

How much energy is required to remove the most loosely bound electron from

a neutral atom of carbon in the gaseous phase?

 1. 801 kJ/mol

 2. 1086 kJ/mol

 3. 1251 kJ/mol

 4. 1000 kJ/mol


Slide43 l.jpg

Chapter 4 – The Periodic Table

Section 3 - Trends in the Periodic Table

THE END


Slide44 l.jpg

Review

How is periodic table arranged:

In order of atomic number not mass as the

original periodic tables were.

Define:

Groups

Go up and down on periodic table

Periods

Go across the periodic table

Alkali Metals

Group 1

Alkaline Earth Metals

Group 2

Group 17

Halogens

Noble Gases

Group 18

Transition Elements

Groups 3-12


Slide45 l.jpg

Left

Right

Yes

No

Yes

No

Yes

No

No

Yes

Lose

Gain

Mercury

Bromine

Francium

Fluorine


Slide46 l.jpg

Ionization Energy

Energy required to remove one valence electron

Electronegativity

Willingness to gain an electron

Atomic Radii

Size of an atom

Ionic Radii

Size of an atom after it has gained/lost an electron(s)


Slide47 l.jpg

Decrease due to increase in

principle energy levels

Increase due to increase

in nuclear charge

Increase due to increase

in nuclear charge

Decrease due to larger radii

Increase due to increase in

principle energy levels

Decrease due to increase

in nuclear charge

Increase due to increase in

principle energy levels. Does

not matter if gaining or losing

electrons

Varies- If gaining electrons

it will increase if losing

electrons it will decrease


  • Login