atoms and elements: are they related? fall 2011. atoms all matter is made of all matter is made of...

Atoms and Elements: Are they Related?

Fall 2011

ATOMSATOMS• ALL MATTER IS MADE OF ALL MATTER IS MADE OF ATOMS• Definition: ATOMS ARE THE Definition: ATOMS ARE THE

SMALLEST PIECE OF MATTER and CANNOT BE BROKEN DOWN INTO A SIMPLER SUBSTANCE.

ATOMS HAVE ATOMS HAVE 3 BASIC PARTS (Subatomic Particles)• PROTONS• NEUTRONS• ELECTRONS

– PROTONS (POSITIVE CHARGE)– ARE FOUND IN THE NUCLEUS AND

MAKE UP MOST OF THE MASS OF THE ATOM.

– VERY IMPORTANT!!! The number of protons an atom has tells you what kind of atom it is!!!!

The Atomic Number is the number of Protons Pg. 158

–NEUTRONS (NO CHARGE)• ARE FOUND IN THE NUCLEUS• MAKE UP PART OF THE MASS

OF THE ATOM

Finding the Number of Neutrons for an Atom

• The protons and neutrons make up the mass of an atom.

• If you know the protons (atomic number) then you can find the number of neutrons by subtracting the atomic mass from the # of protons (atomic number).

atomic mass - # of protons = # of neutrons

Isotopes• Atoms of the same element that have

a different number of neutrons.EX: Carbon

Carbon-12 Carbon-13 Carbon-14

Isotopes & Radioactive Decay

• Atoms are most stable when they have the same number of Pro/Neu in the nucleus…

• So, having more neutrons causes atom to be unstable & “repulsion” builds up.

• Nucleus becomes more stable when the extra particles are released & energy is given off.

• RD is the release of extra nuclear particles & energy.

– ELECTRONSELECTRONS (NEGATIVE CHARGE - )(NEGATIVE CHARGE - )•FOUND IN THE ELECTRON SHELL FOUND IN THE ELECTRON SHELL

(cloud) ORBITING THE NUCLEUS.(cloud) ORBITING THE NUCLEUS.

•TAKES UP MOST OF THE TAKES UP MOST OF THE SPACESPACE IN IN AN ATOM.AN ATOM.

•The # of electrons = the # of protonsThe # of electrons = the # of protons

Valence Electrons

• Outermost electron(s) in the cloud/shell

• 8 is the magic number!!!!!! (octet rule)

Ions

• Atom where the total number of electrons does not equal the total number of protons (atom will have a pos or neg charge)– Cation= pos (loss of e-)– Anion=neg (gain of e-)

– EX: Fe2+, Al3+, O2-

Label the atom below on your packet!

What type of atom is this?

How do you know?

Let’s Break for Questions???

• How many protons should Hydrogen have?

• How about Oxygen?• Which particles are located in the

nucleus of an atom?• Where are the electrons located?

Atomic Size

-A typical atom is about one ten-billionth of a meter in diameter. (THAT’S REALLY, REALLY SMALL AND WHY WE CAN’T SEE THEM WITH A REGULAR MICROSCOPE)

-ATOMIC MASS = Protons + Neutrons.-Most of the atomic mass comes from the nucleus. -Electrons weigh very little. That is why they do not add to the mass of the atom. -They DO contribute to the SIZE.

Isotopes & Mass Number

• So if protons and neutrons contribute to mass, if we have a different number of neutrons, will the mass be affected?

• EX: since C-14 has 8 neutrons, the mass number is 14amu instead of 12amu (C-12).

Discovery of the Atom (pg. 80)

By the early 1800’s, John Dalton proposed that all substances are made up of atoms.

In 1898, J.J. Thomson, proposed that atoms are made up of smaller parts.

In 1911, Ernest Rutherford, proposed that atoms have electrons and a positively charged nucleus.

1)All matter is made of atoms. Atoms are indivisible and indestructible.

2) All atoms of a given element are identical in mass and properties

3) Compounds are formed by a combination of two or more different kinds of atoms.

4) A chemical reaction is a rearrangement of atoms.

Dalton’s Atomic Theory

Niels Bohr’s model of the atom•Electrons revolved around the nucleus in circular paths called orbits.

Current Atomic Theory:

Electron Cloud ModelElectrons travel in regions of various thicknesses called clouds.

• ELEMENTS • DEFINITION: PURE SUBSTANCES MADE OF

ONLY 1 KIND OF ATOM.• ARE THE BUILDING BLOCKS OF MATTER.• CANNOT BE BROKEN DOWN INTO A SIMPLER

SUBSTANCE.• HAVE THEIR OWN UNIQUE SET OF

PROPERTIES THAT NO OTHER ELEMENT HAS.

ELEMENTS

• There are 92 naturally occurring elements on the periodic table. This means they are in nature and not made in a laboratory by scientists.

• As of this year (2011) there are 118 confirmed elements. There are 4 more under investigation and scientific testing.

Let’s Stop for Questions!

• What type of atoms make up the element Lithium? Carbon? Sodium?

• ELEMENTS ARE MADE OF ONLY 1 KIND OF ATOM.

• SOME COMMON ELEMENTS – HYDROGEN (H), HELIUM (He), OXYGEN

(0),– Notice that the first letter is capital and

the next letter is lower case.

Atoms and Elements Activity

• As a group, look at the food labels on the items at your table. Make a list of the items in the left hand side column and in the right hand side column make a list of any elements found in that substance.

• You may use your periodic table to help you identify the elements.

The food item would be:

Cooked Ham

What are the elements that are found on this food label?

QUESTIONS????• What are the most commonly occurring

elements in the food labels?• What items seemed to have the most

amount of elements in them?• Can you predict what that means about

the food item?• Why do you think the baby formula has

such a variety of elements?• Can you predict what the other items on

the food label are if they are not elements?

Wrap UpUse your dry erase boards to write answers

and hold them high!!!

• Protons have what charge?• Electrons have what charge?• Which parts of an atom make up the

mass of the atom?• Elements are made up of?• The element lead is made up of what

kind of atoms?

Periodic Table

• The periodic table is an organized table of each element.

• Each box gives information about each type of element found on Earth.

9.17.00 1:37 PM30 3.3 Periodic Table

Dmitri Mendeleev Dmitri Mendeleev (1869)(1869)In 1869 Mendeleev and Lothar Meyer In 1869 Mendeleev and Lothar Meyer (Germany) published nearly identical (Germany) published nearly identical classification schemes for elements known classification schemes for elements known to date. The periodic table is base on the to date. The periodic table is base on the similarity of properties and reactivities similarity of properties and reactivities exhibited by certain elements. Later, Henri exhibited by certain elements. Later, Henri Moseley ( England,1887-1915) established Moseley ( England,1887-1915) established that each elements has a unique atomic that each elements has a unique atomic number, which is how the current periodic number, which is how the current periodic table is organized.table is organized.

http://www.chem.msu.su/eng/misc/mendeleev/welcome.html

• ELEMENTS ARE ORGANIZED IN THE PERIODIC TABLE ACCORDING TO ATOMIC NUMBER.

• ELEMENTS ARE ORGANIZED IN THE PERIODIC TABLE OF ELEMENTS ACCORDING TO THEIR SIMILAR CHARACTERISTICS

• 3 major groups: metals, nonmetals and metalloids• See pg. 57 in book

Element Info in Each Box

Atomic weightAtomic NumberSymbol Name

Information from the periodic table

Atomic Number- Number of Protons in an atom

Silver = 47 protons

Elements & their symbolsSOME COMMON ELEMENTS

HYDROGEN (H), HELIUM (He), OXYGEN (0),

Notice that the first letter is capital and the next letter is lower case.

Gold- Au (Aurum)

Iron- Fe (Ferrum)

Lead- Pb (Plumbum)

Arrangement of the Periodic table

Periods – Rows are called periods. The elements in these rows change conductivity and number of electrons as you move across the table.

Groups – Columns are called groups or families. These elements have the same properties because of the number of electrons.

How is the Periodic Table Organized?

Even though they skip some squares in between, all of the rows go left to right. When you look at a periodic table, each of the rows is considered to be a different period

Periods

9.17.00 1:37 PM38 3.3 Periodic Table

Across the Periodic Across the Periodic TableTable

Periods:Periods: Are arranged horizontally across the Are arranged horizontally across the periodic table (rows 1-7)periodic table (rows 1-7)

These elements have the same number of valence shells.These elements have the same number of valence shells.1

IA18

VIIIA

12

IIA13

IIIA14

IVA15VA

16VIA

17VIIA

2

33

IIIB4

IVB5

VB6

VIB7

VIIB8 9

VIIIB10 11

IB12IIB

4

5

6

7

2nd Period

6th Period

Groups When a column goes from top to bottom, it's called a group or family.

Groups are often called families because these elements seem to be related.

**Elements in the same group show similarities in their chemical and physical properties.

9.17.00 1:37 PM40 3.3 Periodic Table

Down the Periodic Down the Periodic TableTable

Family:Family: Are arranged vertically down the periodic table Are arranged vertically down the periodic table (columns or (columns or group, 1- 18 or 1-8 A,B)group, 1- 18 or 1-8 A,B)These elements have the same number electrons in the outer most shells, the valence These elements have the same number electrons in the outer most shells, the valence shell.shell.

1IA

18VIIIA

12

IIA13

IIIA14

IVA15VA

16VIA

17VIIA

2

33

IIIB4

IVB5

VB6

VIB7

VIIB8 9

VIIIB10 11

IB12IIB

4

5

6

7

Alkali Family: 1 e- in the valence shell

Alkali Family: 1 e- in the valence shell

Halogen Family: 7 e- in the valence shell

Halogen Family: 7 e- in the valence shell

9.17.00 1:37 PM41 3.3 Periodic Table

Reading the Periodic Table: Reading the Periodic Table: ClassificationClassification

Nonmetals, Metals, Metalloids, Noble gases

9.17.00 1:37 PM42 3.3 Periodic Table

Infamous Families of the Periodic Infamous Families of the Periodic TableTable

Notable families of the Periodic Table and some important members:

1IA

18VIIIA

12

IIA13

IIIA14

IVA15VA

16VIA

17VIIA

2

33

IIIB4

IVB5

VB6

VIB7

VIIB8 9

VIIIB10 11

IB12IIB

4

5

6

7

Alkali

Alkaline (earth)

Transition MetalsTransition Metals

Noble GasNoble GasHalogenHalogen

ChalcogensChalcogens

9.17.00 1:37 PM43 3.3 Periodic Table

Alkali GroupAlkali Group

-Group #1-1 valence electron in outer shell-very reactive with water & other elements-low densities & melting points

9.17.00 1:37 PM44 3.3 Periodic Table

Alkaline Earth GroupAlkaline Earth Group

-Group #2-2 valence electrons in outer shell-very reactive but not as much as alkali-denser, harder & higher melting points

9.17.00 1:37 PM45 3.3 Periodic Table

Transition MetalsTransition Metals

-Groups 3-12-Valence electrons vary-Usually found combined with other elements-higher melting points, good conductors

9.17.00 1:37 PM46 3.3 Periodic Table

Halogen GroupHalogen Group

-Group #17-7 valence electrons in outer shell-most combined to make salts (salt formers)-most are non-metals

9.17.00 1:37 PM47 3.3 Periodic Table

Noble Gas GroupNoble Gas Group

-Group # 18-8 valence electrons in outer shell (the happy gases! )

-NOT REACTIVE

9.17.00 1:37 PM48 3.3 Periodic Table

Periodic Table: Periodic Table: Metallic Metallic arrangementarrangement

Layout of the Periodic Table: Metals vs. nonmetals

1IA

18VIIIA

12

IIA13

IIIA14

IVA15VA

16VIA

17VIIA

2

33

IIIB4

IVB5

VB6

VIB7

VIIB8 9

VIIIB10 11

IB12IIB

4

5

6

7

MetalsMetalsNonmetalsNonmetals

9.17.00 1:37 PM49 3.3 Periodic Table

SummarySummary

Periodic TablePeriodic Table: Map of the Building block of matter

TypeType: Metal, metalloid and NonmetalGroupings: Representative or main, transition and Lanthanide/Actanides

FamilyFamily: Elements in the same column have similar chemical property because of similar valence electronsAlkali, Alkaline, halogens, noble gases

PeriodPeriod:: Elements in the same row have valence electrons in the same shell.

The Periodic Table Of Elements

Elements are classified:*Metals*Nonmetals*Metalloids

Xenon

Scandium

Properties of a metal

*Good conductors – conducts heat or electricity*Malleable - flattened*Ductile – can be made into wires*Shiny- you can see you reflection

Iron

Gold

Magnesium

Properties of a Nonmetal*Not malleable – cannot be flattened*Not shiny*Poor conductors

Helium

Chlorine

Bromine

Properties of Metalloids

•Semiconductors – Average conductors•Shiny but brittle

ArsenicSilicon

Boron

GOLD (AU)

Sulfur

Silver

ELEMENTS IN OUR BODIES

IODINE

• 1.Oxygen (65%) • 2.Carbon (18%) • 3.Hydrogen (10%) • 4.Nitrogen (3%) • 5.Calcium (1.5%) • 6.Phosphorus (1.0%) • 7.Potassium (0.35%) • 8.Sulfur (0.25%) • 9.Sodium (0.15%) • 10.Magnesium (0.05%) • 11.Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine,

Iodine, Manganese, Cobalt, Iron (0.70%) • 12.Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium,

Arsenic, Bromine (trace amounts)

99% of the mass of the human body is made up of only six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Every organic molecule contains carbon. Since 65-90% of each body cell consists of water (by weight), it isn't surprising that oxygen and hydrogen are major components of the body

Elements in the body

Oxygen Carbon Hydrogen Nitrogen

Calcium Phosphorus Potassium Sodium

Chlorine Magnesium Sulfur

GASESGASES

FLUORINE KRYPTON

NEON

NITROGEN

Atoms to Elements to ???

• ELEMENTS & COMPOUNDS ARE THE BASIC BUILDING BLOCKS OF MATTER

• EACH ELEMENT & COMPOUND HAS SPECIFIC PROPERTIES

COMPOUNDS ARE MADE OF 2 OR MORE DIFFERENT KINDS OF ATOMS/Elements BONDED

TOGETHER

COMPOUNDS ARE MADE OF 2 OR MORE DIFFERENT KINDS OF ATOMS

BONDED TOGETHER

Compounds

http://web.neo.edu/rjones/Pages/1014new/Lecture/chemistry/chapter_9/pages/chemical_bonds.html

• COMPOUNDS ARE MADE OF 2 OR MORE DIFFERENT KINDS OF ATOMS BONDED TOGETHER

• FOR A COMPOUND TO FORM, A CHEMICAL CHANGE MUST TAKE PLACE (A REACTION)

• THE ELEMENTS THAT COMBINE MAKE A NEW SUBSTANCE WITH NEW PHYSICAL PROPERTIES

• COMPOUNDS CANNOT BE BROKEN DOWN PHYSICALLY. REQUIRES A CHEMICAL CHANGE

• MORE COMMON THAN ELEMENTS

+ =

NaCl TABLE SALT

• COMPOUNDS ARE IDENTIFIED BY A CHEMICAL FORMULA

• THE ELEMENTS THAT COMBINE TO MAKE THE COMPOUND CHANGE PROPERTIES

+ =

NaCl TABLE SALT

Atomic Structure & Chemical Bonds

• Octet rule= when atoms of elements react, they ten to lose, gain or share electrons to achieve the same electron arrangement as the noble gases.

3 Ways Elements Bond

• Ionic= loss or gain of electron (metal + non-metal)

• Metallic= metal atoms share pooled electrons– (pooling=electrons gathered together)

• Covalent=sharing of electrons (non-metal elements)

Ionic

Covalent

• Carbon forms lots of covalent bonds

Metallic

• A way of writing how many atoms are in a compound.

Chemical Formulas

Written as: C4H10

Butane

Written as: CH4

Methane

Subscripts= how many atoms

= how many total molecules

• FeO2

• H2O

• C6H12O6

• 2Li + 2O2

Chemical Changes Through Chemical ReactionsA chemical reaction – Process in which the physical and chemical properties of the original substance(s) CHANGE as new substances with different properties are formed.

A burning match is a good example of a chemical reaction.

Application of a spark to the chemicals on the match head start the chemical reaction.

Signs of a chemical change – heat given off, light given off, new substance formed – black material on the match head when the fire is extinguished.

Parts of a Chemical Reaction

Reactants – Substances that begins the chemical reaction (chemicals on match head)Products – Substances produced in the reaction (black material on match)

In other words: REACTANTS CHANGE INTO PRODUCTS

CHEMICAL EQUATIONS• Chemical equations are symbols used to

describe the details of a chemical reaction. • Shows how the reactants changed into the

product. • This involves indicating all the atoms

involved in the reaction.

Fe + O2 FeO2

Reactants:Iron and oxygen

Product:Ferrous oxide(rust)Plus Sign:

Shows substances combine

Arrow:Means “yields”takes the place

of an = sign

Law of Conservation of Matter Matter cannot be created or destroyed, it

just changes forms.The total mass of the reactants must equal the total mass of the product.

Law of Conservation of Mass

http://www.sky-web.net/science/balancing_chemical_equations_examples.htm

Alka-Seltzer and Water

Balancing Equations• The number of atoms of the reactants

must equal the number of atoms in the product. (Law of Conservation of Matter)

Ex: 2Na + Cl2 -> 2NaCl

4P + 5O2 -> P4O10

Balancing Equations

• Rules– Make sure that all atoms are equal on both

sides.– You can only add coefficients.

• Changing the subscripts will change the identity of the compound.

– H2O & H2O2

EX: 2Na + Cl2 -> 2NaCl

H2 + O2 -> 2H2O

(Not balanced… So…) 2H2 + O2 -> 2H2O

Balancing Chemical Equations

Hg + O2 HgO

H2 + Cl HCl

Mg + O2 MgO

O2 + H2 H2O

CH4 + O2 CO2 + H2O

Fe + Cl2 FeCl3

Hg + O2 HgO

H2 + Cl HCl

Mg + O2 MgO

O2 + H2 H2O

Fe + Cl2 FeCl3

CH4 + O2 CO2 + H2O

• CAN YOU TELL WHICH IS A MOLECULE CAN YOU TELL WHICH IS A MOLECULE OF AN ELEMENT OR A COMPOUND? OF AN ELEMENT OR A COMPOUND? WHICH SHOWS AN ATOM?WHICH SHOWS AN ATOM?

• MOLECULES ARE 2 OR MORE ATOMS ATTACHED TOGETHER– THEY CAN BE THE SAME KIND

(ELEMENTS)– THEY CAN BE DIFFERENT KINDS

(COMPOUNDS)

Examples: H2O, NaCl.

9.17.00 1:37 PM93 3.3 Periodic Table

Periodic Table: electron Periodic Table: electron behaviorbehaviorThe periodic table can be classified by the behavior of their electrons

1IA

18VIIIA

12

IIA13

IIIA14

IVA15VA

16VIA

17VIIA

2

33

IIIB4

IVB5

VB6

VIB7

VIIB8 9

VIIIB10 11

IB12IIB

4

5

6

7

West (South) Mid-plains East (North)METALS

AlkaliAlkaline

Transition

METALLOID NON-METALSNoble gasHalogensCalcogens

These elementstend to give up

e- and formCATIONS

These elementswill give up e- or

accept e-

These elementstend to accept

e- and formANIONS