AtomsAtoms All matter is made of themAll matter is made of them Idea came from Greek philosopher Idea came from Greek philosopher

DemocritusDemocritus 400 B.C400 B.C Greek word “atomos” – not to be cutGreek word “atomos” – not to be cut Did not use scientific methodDid not use scientific method No experiments to support ideaNo experiments to support idea

Atoms are very small, and they are made up of even Atoms are very small, and they are made up of even smaller subatomic particles.smaller subatomic particles.

Parts of AtomsParts of Atoms Atoms can be broken.Atoms can be broken. There are many different particlesThere are many different particles We will learn about the three most We will learn about the three most

important to chemistryimportant to chemistry ProtonProton – positively charged, big mass – positively charged, big mass Electron Electron – negatively charged, very small – negatively charged, very small

massmass NeutronNeutron – no charge, about the same – no charge, about the same

mass as a protonmass as a proton

Parts of AtomsParts of Atoms Proton and neutron are about 2000 times Proton and neutron are about 2000 times

heavier than the electronheavier than the electron Protons and neutrons are located in the Protons and neutrons are located in the

nucleusnucleus Electrons outside the nucleusElectrons outside the nucleus An atom is mostly emptyAn atom is mostly empty If the atom were the size of a baseball If the atom were the size of a baseball

stadium, the nucleus would be the size of stadium, the nucleus would be the size of a marblea marble

〉 What is the difference between protons, neutrons, What is the difference between protons, neutrons, and electrons?and electrons?

〉 The three main subatomic particles are distinguished The three main subatomic particles are distinguished by mass, charge, and location in the atom.by mass, charge, and location in the atom.

Draw Diagram

Each element has a unique number of protonsEach element has a unique number of protons..

Unreacted atoms have no overall charge.Unreacted atoms have no overall charge. Because there is an equal number of protons and electrons, the Because there is an equal number of protons and electrons, the

charges cancel out.charges cancel out.

The The electric force electric force holds the atom togetherholds the atom together.. Positive protons are attracted to negative electrons by the Positive protons are attracted to negative electrons by the

electric force.electric force. This force holds the atom together.This force holds the atom together.

Counting the piecesCounting the pieces Atomic Number-Atomic Number- the number of protons the number of protons Determines the type of atom and elementDetermines the type of atom and element Mass number-Mass number- number of protons and number of protons and

neutronsneutrons All the heavy piecesAll the heavy pieces Electrons are the same as protons if Electrons are the same as protons if

neutral.neutral. If an ion, it gained or lost electronsIf an ion, it gained or lost electrons

The Mass of AtomsThe Mass of Atoms Very, very smallVery, very small Can’t use gramsCan’t use grams Use the Atomic Mass Unit (amu)Use the Atomic Mass Unit (amu) One twelfth the mass of a carbon-12 atomOne twelfth the mass of a carbon-12 atom Since carbon-12 has 6 protons and 6 Since carbon-12 has 6 protons and 6

neutrons makes the mass of a proton or neutrons makes the mass of a proton or neutron 1.0 amuneutron 1.0 amu

Atomic MassAtomic Mass Mass of the average atomMass of the average atom Since there are isotopes of atoms two Since there are isotopes of atoms two

things affect the averagethings affect the average The mass of the isotopesThe mass of the isotopes How much of each isotope there isHow much of each isotope there is

These are the decimal numbers on the These are the decimal numbers on the periodic tableperiodic table

Atomic Number and Atomic Number and Mass NumberMass Number

〉 What do atoms of an element have in common What do atoms of an element have in common with other atoms of the same element?with other atoms of the same element?

〉 Atoms of each element have the same number Atoms of each element have the same number of protons, but they can have different of protons, but they can have different numbers of neutrons.numbers of neutrons.

The atomic number equals the number of protons.The atomic number equals the number of protons. atomic number:atomic number: the number of protons in the nucleus of an the number of protons in the nucleus of an

atomatom

The mass number equals the total number of The mass number equals the total number of subatomic particles in the nucleus.subatomic particles in the nucleus. mass number:mass number: the sum of the numbers of protons and neutrons the sum of the numbers of protons and neutrons

in the nucleus of an atomin the nucleus of an atom

Atomic MassesAtomic Masses〉 What unit is used to express atomic mass?What unit is used to express atomic mass?

〉 Because working with such tiny masses is difficult, Because working with such tiny masses is difficult, atomic masses are usually expressed in unified atomic masses are usually expressed in unified atomic mass units.atomic mass units.

unified atomic mass unit: unified atomic mass unit: a unit of mass that a unit of mass that describes the mass of an atom or molecule; it describes the mass of an atom or molecule; it is exactly 1/12 the mass of a carbon atom with is exactly 1/12 the mass of a carbon atom with mass number 12 (symbol, u)mass number 12 (symbol, u)

Average atomic mass is a weighted Average atomic mass is a weighted averageaverage..

– Isotope abundance determines the average

atomic mass.– Example: Chlorine-35 is

more abundant than chlorine-37, so

chlorine’s average atomic mass (35.453 u) is closer to 35 than to

37.

Atomic MassAtomic Mass Two isotopes of copper Two isotopes of copper

72% copper-6372% copper-63 28% copper-6528% copper-65

Makes the average 63.56 amuMakes the average 63.56 amu

IsotopesIsotopes Atoms of the same type can have different Atoms of the same type can have different

numbers of neutronsnumbers of neutrons These are These are isotopesisotopes They behave identicallyThey behave identically They just weigh different amountsThey just weigh different amounts Mass number is written after the nameMass number is written after the name Hydrogen – 1Hydrogen – 1 Hydrogen – 2Hydrogen – 2

Atomic Number and Atomic Number and Mass Number, Mass Number, continuedcontinued

IsotopesIsotopes〉 Why do isotopes of the same element have Why do isotopes of the same element have

different atomic masses?different atomic masses?

〉 Isotopes of an element vary in mass because Isotopes of an element vary in mass because their numbers of neutrons differ.their numbers of neutrons differ.

Isotopes, Isotopes, continuedcontinued

Some isotopes are more common than Some isotopes are more common than others.others. radioisotopes:radioisotopes: unstable isotopes that emit radiation and unstable isotopes that emit radiation and

decay into other isotopesdecay into other isotopes

The number of neutrons can be The number of neutrons can be calculated.calculated. number of neutrons = mass number – atomic numbernumber of neutrons = mass number – atomic number

The mole is useful for counting small particles.The mole is useful for counting small particles.

mole:mole: the SI base unit used to measure the the SI base unit used to measure the amount of a substanceamount of a substance whose number of particles whose number of particles is the same as the number of atoms of carbon in is the same as the number of atoms of carbon in exactly 12 g of carbon-12 (abbreviation, mol)exactly 12 g of carbon-12 (abbreviation, mol)

1 mol = 602, 213, 670, 000, 000, 000, 000, 000 particles1 mol = 602, 213, 670, 000, 000, 000, 000, 000 particles

This number, usually written as 6.022 × 10This number, usually written as 6.022 × 102323, is called , is called Avogadro’s Avogadro’s number.number.

Moles and grams are related.Moles and grams are related. molar massmolar mass = = the mass in grams of one mole of a the mass in grams of one mole of a

substancesubstance Example: 1 mol of carbon-12 atoms has a mass of Example: 1 mol of carbon-12 atoms has a mass of

12.00 g, so the molar mass of carbon-12 is 12.00 g/mol12.00 g, so the molar mass of carbon-12 is 12.00 g/mol

You can convert between moles and You can convert between moles and grams.grams.

Math SkillsMath SkillsConverting Moles to GramsConverting Moles to GramsDetermine the mass in grams of 5.50 mol of iron.Determine the mass in grams of 5.50 mol of iron.

1. List the given and unknown values. 1. List the given and unknown values.

Given:Given: amount of iron = 5.50 mol Feamount of iron = 5.50 mol Femolar mass of iron = 55.84 g/mol Fe*molar mass of iron = 55.84 g/mol Fe*Unknown:Unknown: mass of iron = ? g Femass of iron = ? g Fe

**Use the periodic table to find molar masses. The average Use the periodic table to find molar masses. The average atomic mass of an element is equal to the molar mass of the atomic mass of an element is equal to the molar mass of the element. This book rounds values to the hundredths place.element. This book rounds values to the hundredths place.

Math Skills, Math Skills, continuedcontinued2. Write down the conversion factor that converts moles 2. Write down the conversion factor that converts moles

to grams.to grams.The conversion factor you choose should have what you The conversion factor you choose should have what you are trying to find (grams of Fe) in the numerator and what are trying to find (grams of Fe) in the numerator and what you want to cancel (moles of Fe) in the denominator.you want to cancel (moles of Fe) in the denominator.

3. Multiply the amount of iron by this conversion factor, 3. Multiply the amount of iron by this conversion factor, and solveand solve..

55.84 g Fe1 mol Fe

55.84 g Fe5.50 mol Fe 307 g Fe1 mol Fe

Compounds also have molar masses.Compounds also have molar masses.

To find the molar mass of a compound, add up the molar To find the molar mass of a compound, add up the molar masses of all of the atoms in a molecule of the compound. masses of all of the atoms in a molecule of the compound.

Example: finding the molar mass of water, HExample: finding the molar mass of water, H22OOmolar mass of O = 16.00 g/molmolar mass of O = 16.00 g/molmolar mass of H = 1.01 g/mol molar mass of H = 1.01 g/mol molar mass of Hmolar mass of H22O = (2 × 1.01 g/mol) + O = (2 × 1.01 g/mol) +

16.00 g/mol = 18.02 g/mol16.00 g/mol = 18.02 g/mol

Energy LevelEnergy Level Describe the path the electron takes Describe the path the electron takes

around the nucleusaround the nucleus Farther from nucleus is more energyFarther from nucleus is more energy Gain energy they move awayGain energy they move away Lose energy they move towardLose energy they move toward Only certain energies are allowed in each Only certain energies are allowed in each

atomatom

Energy Energy LevelsLevels

2e-

8e-

8e-Like an elevatorLike an elevatorit can only be on certain it can only be on certain floorsfloorsNever in betweenNever in betweenEnergy levels get closer Energy levels get closer together the higher you together the higher you gogoEach has room for a Each has room for a certain number of certain number of electronselectrons

Current ModelCurrent Model Treats electrons as waves, not particlesTreats electrons as waves, not particles Talks only about the probability of finding Talks only about the probability of finding

an electronan electron Region called the electron cloudRegion called the electron cloud Where are the blades in a fan?Where are the blades in a fan? It is impossible to know the exact location It is impossible to know the exact location

and the speed and direction of an electronand the speed and direction of an electron

OrbitalsOrbitals Regions where you have a chance of Regions where you have a chance of

finding the electronfinding the electron There are different types of orbitalsThere are different types of orbitals

s, p, d, fs, p, d, f Each has its own shape or shapesEach has its own shape or shapes Each shape has room for two electronsEach shape has room for two electrons Each can be found in the energy levelsEach can be found in the energy levels

S orbitalS orbital Shaped like a sphereShaped like a sphere Room for 2 electronsRoom for 2 electrons

P orbitalsP orbitals 3 dumbbell-shaped regions3 dumbbell-shaped regions One on each axes of a 3-D graphOne on each axes of a 3-D graph

P orbitalsP orbitals Each shape can hold two electronsEach shape can hold two electrons Total of 6Total of 6

d orbitalsd orbitals Five different shapesFive different shapes More complexMore complex Each can hold 2 electronsEach can hold 2 electrons Total of 10 electronsTotal of 10 electrons

d orbitalsd orbitals

f orbitalsf orbitals seven different shapesseven different shapes Much more complexMuch more complex Each can hold 2 electronsEach can hold 2 electrons Total of 14 electronsTotal of 14 electrons

f orbitalsf orbitals

Valence electronsValence electrons The electrons in the outermost energy The electrons in the outermost energy

levellevel Responsible for most of the chemical Responsible for most of the chemical

propertiesproperties When two atoms interact, the outside When two atoms interact, the outside

electrons are the ones affectedelectrons are the ones affected

Elements and the Elements and the Periodic TablePeriodic Table

Where did the Where did the elements come elements come

from?from?

AlchemyAlchemyWhat was the main objective of early What was the main objective of early

alchemists?alchemists?To make gold from lead.To make gold from lead.

Why was this impossible?Why was this impossible?Add 18 protons to nucleus, present Add 18 protons to nucleus, present

technology is only 1 and only under technology is only 1 and only under extreme circumstances.extreme circumstances.

What are What are synthetic elementssynthetic elements??Elements created in the labElements created in the lab. Usually . Usually

unstable and may be radioactive.unstable and may be radioactive.

How many How many elements are naturally occurringelements are naturally occurring??9393

Where are elements created?Where are elements created?In the center of stars.In the center of stars.

What is a What is a nuclear reaction?nuclear reaction?A reaction that A reaction that changes the composition of changes the composition of

the nucleus of an atom.the nucleus of an atom.

What is a transmutation?What is a transmutation?Changing one nucleus into another by either Changing one nucleus into another by either

radioactive disintegration or bombardment radioactive disintegration or bombardment of the nucleus with other particles.of the nucleus with other particles.

What is a cyclotron?What is a cyclotron?A device that accelerates charges particles A device that accelerates charges particles

to high energy states. Then they are to high energy states. Then they are collided with atomic nuclei forming atoms collided with atomic nuclei forming atoms of a higher atomic number.of a higher atomic number.

What is a synchrotron?What is a synchrotron?A device that times the impulses of energy A device that times the impulses of energy

in a cyclotron to match the acceleration of in a cyclotron to match the acceleration of the particle. The particles collide forming the particle. The particles collide forming super heavy elements.super heavy elements.

What are super heavy elements?What are super heavy elements?An element with an atomic number greater An element with an atomic number greater

that 103.that 103.

The Periodic TableThe Periodic Table Listed in order of increasing number of Listed in order of increasing number of

protonsprotons When you do this the properties of the When you do this the properties of the

elements repeat.elements repeat. Periodic Law-Periodic Law- when the elements are when the elements are

arranged in order of increasing number of arranged in order of increasing number of protons, the properties tend to repeat in a protons, the properties tend to repeat in a patternpattern

What makes a What makes a group of group of

elements?elements?

What do you know about the periodic table?What do you know about the periodic table?

Arranged by atomic #Arranged by atomic #

Gives average atomic massGives average atomic mass

How are elements different?How are elements different?Solids, liquids and gases.Solids, liquids and gases.ColorsColors

How are elements alike?How are elements alike?Chemical propertiesChemical properties

Modern Periodic TableModern Periodic TableWhat was known in the mid 1800’s?What was known in the mid 1800’s?Elements had atomic massesElements had atomic massesSome elements had similar physical and Some elements had similar physical and

chemical properties.chemical properties.John Newlands noticed that when the 16 John Newlands noticed that when the 16

known elements were placed in order of known elements were placed in order of atomic mass that the elements in the atomic mass that the elements in the same column had similar propertiessame column had similar properties..

Dimitri Mendeleev: 1870Dimitri Mendeleev: 187063 known elements63 known elements..Used Newlands method to Used Newlands method to arrange elements arrange elements

according to atomic mass and properties.according to atomic mass and properties.

The table had gaps and some of the atomic The table had gaps and some of the atomic masses were reversedmasses were reversed..

The gaps were undiscovered elements.The gaps were undiscovered elements.

OrganizationOrganization Elements are organized based onElements are organized based on

Chemical PropertiesChemical Properties Valence NumberValence Number (the number of electrons in (the number of electrons in

the outside energy level)the outside energy level) Families or Groups behave the same way Families or Groups behave the same way

chemically because they have the same # of chemically because they have the same # of valence electronsvalence electrons. (Vertical columns). (Vertical columns)

Periods have the same number of energy Periods have the same number of energy levels/shells/electron clouds levels/shells/electron clouds (Horizontal (Horizontal Rows)Rows)

Periodic Table Periodic Table ArrangementArrangement

Metals:Metals: Good conductors, all but mercury solid at room Good conductors, all but mercury solid at room

temperature, malleable, ductile, groups 1- 12 temperature, malleable, ductile, groups 1- 12 and some elements of 13-16.and some elements of 13-16.

Transition Metals: Transition Metals: Inclusive of groups 3-12, varied properties.Inclusive of groups 3-12, varied properties.Nonmetals: Nonmetals: Groups 17 & 18, with some elements in groups 14-Groups 17 & 18, with some elements in groups 14-

16. Poor conductors, brittle, varied properties.16. Poor conductors, brittle, varied properties.

Periodic Table Periodic Table ArrangementArrangement

Metalloids/Semiconductors: Metalloids/Semiconductors: Properties of both metals and nonmetals. Properties of both metals and nonmetals.

Usually good conductors at high Usually good conductors at high temperature.temperature.

The Periodic TableThe Periodic TableH

Li

Na

K

Rb

Cs

Fr

Be

Mg

Ca

Sr

Ra

Ba

F

Cl

Br

I

Uus

At

O

S

Se

Te

Uuh

Po

N

P

As

Sb

Uup

Bi

C

Si

Ge

Sn

Uuq

Pb

B

Al

Ga

In

Uut

Tl

Sc Ti V Cr Mn Fe Co Ni Cu Zn

Y Zr Nb Mo Tc Ru Rh Pd Ag Cd

Lu Hf Ta W Re Os Ir Pt Au Hg

He

Ne

Ar

Kr

Xe

RnUuo

La Ce Pr Nd Pm Sm Eu Gd Tb

Ac Th Pa U Np Pu AmCm Bk

Dy

Cf

Ho

Es

Er

Fm

Tm

Md

Yb

No

H

Li

Na

K

Rb

Cs

Fr

Be

Mg

Ca

Sr

Ra

Ba

B

Al

Ga

In

Uut

TlLr Rf Db Sg Bh Hs Mt Uun Uuu Uub

Sc Ti V Cr Mn Fe Co Ni Cu Zn

Y Zr Nb Mo Tc Ru Rh Pd Ag Cd

Lu Hf Ta W Re Os Ir Pt Au HgLr Rf Db Sg Bh Hs Mt Uun Uuu Uub

C

Si

Ge

Sn

Uuq

Pb

N

P

As

Sb

Uup

Bi

O

S

Se

Te

Uuh

Po

F

Cl

Br

I

Uus

At

He

Ne

Ar

Kr

Xe

RnUuo

La Ce Pr Nd Pm Sm Eu Gd Tb

Ac Th Pa U Np Pu AmCm Bk

Dy

Cf

Ho

Es

Er

Fm

Tm

Md

Yb

No

Group 1 all have one Group 1 all have one electron in their outside electron in their outside s orbitals orbital

Group 2 all have two Group 2 all have two electrons in their outside electrons in their outside s orbitals orbital

The middle of the table is 10 elements The middle of the table is 10 elements widewide

This is where the d orbitals are fillingThis is where the d orbitals are filling

On the right hand side Group 13 -18 the s On the right hand side Group 13 -18 the s orbitals are full, and the p orbitals are orbitals are full, and the p orbitals are fillingfilling

Group 13 s has 2 eGroup 13 s has 2 e--

p has 1 ep has 1 e--

Group 14 s has 2 eGroup 14 s has 2 e--

p has 2 ep has 2 e--

Group 18 s has 2 eGroup 18 s has 2 e--

p has 6 ep has 6 e--

p and s both fullp and s both full

IonsIons Atoms with a chargeAtoms with a charge Different number of protons and electronsDifferent number of protons and electrons Form by changing the number of electronsForm by changing the number of electrons IonizationIonization- adding or removing electrons - adding or removing electrons

from an atom or group of atomsfrom an atom or group of atoms Two typesTwo types

CationsCations Ions with a positive chargeIons with a positive charge More protons than electronsMore protons than electrons Formed by losing electronsFormed by losing electrons Happens to atoms with few valence Happens to atoms with few valence

electronselectrons Lose electrons to get down to full outside Lose electrons to get down to full outside

energy levelenergy level Written as a superscript NaWritten as a superscript Na+ + CaCa2+2+

AnionsAnions Negative ionsNegative ions More electrons than protonsMore electrons than protons Form by gaining electronsForm by gaining electrons Happens to atoms with many valence Happens to atoms with many valence

electronselectrons Fill up outer energy levelFill up outer energy level Written as a superscript FWritten as a superscript F- - OO2-2-

MetalsMetals

MetalsMetals Luster – shiny.Luster – shiny. Ductile – drawn into wires.Ductile – drawn into wires. Malleable – hammered into sheets.Malleable – hammered into sheets. Conductors of heat and electricity.Conductors of heat and electricity.

Transition metals The Group B

elements

Non-metals Dull Brittle Nonconductors

- insulators

Metalloids or Semimetals Properties of both Semiconductors

Group 1 are the alkali metalsGroup 1 are the alkali metals Group 2 are the alkaline earth metalsGroup 2 are the alkaline earth metals

Group 17 is called the HalogensGroup 17 is called the Halogens Group 18 are the noble gasesGroup 18 are the noble gases

FamiliesFamilies1A/1: alkali metals, 1 valence electron, extremely 1A/1: alkali metals, 1 valence electron, extremely reactive, usually with halogensreactive, usually with halogensEasily lose it to form a 1+ ionEasily lose it to form a 1+ ionSoft , Tarnish readily, Low melting points, Low Soft , Tarnish readily, Low melting points, Low densities, Violently reactive densities, Violently reactive 2A/2: alkaline earth metals, 2 valence electrons, 2A/2: alkaline earth metals, 2 valence electrons, very reactive usually with Oxygen familyvery reactive usually with Oxygen family

Lose them to form a 2+ ionLose them to form a 2+ ionSoft, silver colored, higher density and melting Soft, silver colored, higher density and melting points than Alkali metalspoints than Alkali metals

Alkali Metals Alkaline Alkali Metals Alkaline MetalsMetals

Potassium

Magnesium

Transition MetalsTransition Metals Less reactiveLess reactive Often found alone in natureOften found alone in nature Form many different ionsForm many different ions

FamiliesFamilies3A/13: boron family, 3 valence electrons, 3A/13: boron family, 3 valence electrons,

mediocre reactivity, usually with Nitrogen mediocre reactivity, usually with Nitrogen familyfamily

4A/14: Carbon Family, 4 valence electrons, 4A/14: Carbon Family, 4 valence electrons, slightly reactiveslightly reactive

FamiliesFamilies5A/15: Nitrogen Family5A/15: Nitrogen Family

6A/16 Oxygen Family6A/16 Oxygen Family

7A/ 17: Halogens, extremely reactive, combine 7A/ 17: Halogens, extremely reactive, combine with metals to form salts, disinfectants, variety of with metals to form salts, disinfectants, variety of colors. Gain one electron to form a 1- ioncolors. Gain one electron to form a 1- ion

8A/18: Noble/Inert Gases, nonreactive 8A/18: Noble/Inert Gases, nonreactive Colorless and Odorless at room temperature Colorless and Odorless at room temperature

Halogens Noble GasesHalogens Noble Gases

Lanthanides:Lanthanides:Shiny reactive metals with irregular electron Shiny reactive metals with irregular electron

configurations. configurations.

Actinides:Actinides:Unstable arrangements of protons, Unstable arrangements of protons,

radioactive, example uranium.radioactive, example uranium.