MATTER: Atomic StructureMATTER: Atomic Structure

ElementsElements

The elements, alone The elements, alone or in combinations, or in combinations, make up our bodies, make up our bodies, our world, our sun, our world, our sun, and in fact, the entire and in fact, the entire universe.universe.

Definition: a Definition: a substance that cannot substance that cannot be broken down into a be broken down into a simpler substance by simpler substance by chemical means..chemical means..

The most abundant element in the The most abundant element in the earth’s crust is oxygen.earth’s crust is oxygen.

90 elements occur naturally on earth. The others have been created in labs.

What is an atom?What is an atom?

The smallest unit of an elementThe smallest unit of an elementThey can’t be broken downThey can’t be broken downAtoms are so small we could fit over a Atoms are so small we could fit over a

million atoms inside this period .million atoms inside this period .

Subatomic ParticlesSubatomic Particles Protons and electrons are the only particles that have a Protons and electrons are the only particles that have a

charge.charge. PROTONS have a (+) positive charge (in nucleus) PROTONS have a (+) positive charge (in nucleus) ELECTRONS have a (-) negative chargeELECTRONS have a (-) negative charge NEUTONS have no charge (in nucleus) NEUTONS have no charge (in nucleus)

Protons and neutrons have essentially the Protons and neutrons have essentially the same mass.same mass.

The mass of an electron is so small we The mass of an electron is so small we ignore it.ignore it.

The NucleusThe Nucleus

The protons and neutrons packed closely The protons and neutrons packed closely together make up the nucleustogether make up the nucleus

Located in the CENTER of the atomLocated in the CENTER of the atom It is Positively chargedIt is Positively chargedMakes up most of the mass but not Makes up most of the mass but not

volumevolumeEXAMPLE: Gumdrop/Football stadiumEXAMPLE: Gumdrop/Football stadium

Electron CloudElectron Cloud

Electrons move inside this regionElectrons move inside this regionSince opposite charges attract each otherSince opposite charges attract each otherThe negative (electrons) are attracted to The negative (electrons) are attracted to

the positively charged nucleusthe positively charged nucleus

Atomic NumberAtomic Number

The number of The number of protons in the protons in the nucleusnucleus is called the is called the atomic number. atomic number.

No two elements, No two elements, have the same have the same number of protons.number of protons.

Bohr Model of Hydrogen Atom

Wave Model

Atomic NumberAtomic Number

Atomic MassAtomic Mass

The mass of an atom in atomic mass units (amu) The mass of an atom in atomic mass units (amu) is is the the total number of protons and neutrons total number of protons and neutrons in the atom.in the atom.

Atomic MassAtomic Mass

Atomic Mass refers to Atomic Mass refers to the “weight” of the the “weight” of the atom.atom.

It is derived at by It is derived at by adding the number of adding the number of protons with the protons with the number of neutrons. number of neutrons.

HOW TO READ THE HOW TO READ THE PERIODIC TABLEPERIODIC TABLE

How to find protonsHow to find protons::

The number of protons equals the atomic The number of protons equals the atomic number number

How to find neutronsHow to find neutrons::

1. Find the atomic weight of the element1. Find the atomic weight of the element2. Find the number of protons of the 2. Find the number of protons of the elementelement3. Subtract the number of protons from the 3. Subtract the number of protons from the atomic weight of the elementatomic weight of the element

How to find the electrons and rings:How to find the electrons and rings:

1. Find the electrons in each ring at the 1. Find the electrons in each ring at the bottom of your elementbottom of your element2. The number of electrons on each ring is 2. The number of electrons on each ring is given from left to rightgiven from left to right3. The first number on the left represents 3. The first number on the left represents the first ring outside of the nucleusthe first ring outside of the nucleus

IntroductionIntroductionThe periodic table is made up of rows of elements The periodic table is made up of rows of elements

and columns.and columns.An element is identified by its chemical symbol.An element is identified by its chemical symbol.The number above the symbol is the atomic numberThe number above the symbol is the atomic numberThe number below the symbol is the rounded The number below the symbol is the rounded

atomic weight of the element.atomic weight of the element.A row is called a A row is called a periodperiodA column is called a A column is called a group group

Names of ElementsNames of ElementsThe first 103 elements have internationally The first 103 elements have internationally

accepted names, which are derived from:accepted names, which are derived from:The compound or substance in which the element was The compound or substance in which the element was

discovereddiscoveredAn unusual or identifying property of the elementAn unusual or identifying property of the elementPlaces, cities, and countriesPlaces, cities, and countriesFamous scientistsFamous scientistsGreek mythologyGreek mythologyAstronomical objects.Astronomical objects.

Dmitri MendeleevDmitri Mendeleev Russian scientist born in Siberia in 1834, Russian scientist born in Siberia in 1834,

is known as the father of the periodic is known as the father of the periodic table of the elements. table of the elements.

The periodic table of the elements is an The periodic table of the elements is an important tool used by students and important tool used by students and chemists around the world to help them chemists around the world to help them understand and simplify the often understand and simplify the often complex world of chemical reactions.complex world of chemical reactions.

Not only did Mendeleev arrange the Not only did Mendeleev arrange the periodic table of the elements, he also periodic table of the elements, he also wrote and published a 2 volume wrote and published a 2 volume chemistry book entitled chemistry book entitled Principles of Principles of ChemistryChemistry as there was no thorough as there was no thorough chemistry textbook at the time. chemistry textbook at the time.

The Big TaskThe Big Task

Mendeleev set out to identify a pattern in the Mendeleev set out to identify a pattern in the elements. elements.

Mendeleev looked at many pieces of evidence Mendeleev looked at many pieces of evidence and made an important observation that some and made an important observation that some elements have similar chemical and physical elements have similar chemical and physical properties. properties.

Mendeleev's hunch was that these similarities Mendeleev's hunch was that these similarities were the key to unlocking the hidden pattern of were the key to unlocking the hidden pattern of the elements.the elements.

Mendeleev then embarked on the tedious task Mendeleev then embarked on the tedious task of organizing all known information for every of organizing all known information for every element to help him decipher the pattern. element to help him decipher the pattern.

To begin his task, Mendeleev wrote facts about the To begin his task, Mendeleev wrote facts about the elements on individual paper cards. On these cards, elements on individual paper cards. On these cards, Mendeleev wrote information such as the elements' melting Mendeleev wrote information such as the elements' melting points, densities, colors, atomic masses (the average mass points, densities, colors, atomic masses (the average mass of one atom of that element), and bonding powers (the of one atom of that element), and bonding powers (the number of chemical bonds an element can form).number of chemical bonds an element can form).

Once Mendeleev's cards were made, he tried arranging Once Mendeleev's cards were made, he tried arranging them in various ways. Finally, Mendeleev noticed that them in various ways. Finally, Mendeleev noticed that patterns appeared when the elements were arranged in patterns appeared when the elements were arranged in order of increasing atomic mass. order of increasing atomic mass.

Mendeleev's table was not perfect, however. Arranging the Mendeleev's table was not perfect, however. Arranging the elements by increasing atomic mass left three blank elements by increasing atomic mass left three blank spaces in the table. spaces in the table.

This first periodic table of the elements was published in This first periodic table of the elements was published in 1869. 1869.

The word "periodic" means that there is a The word "periodic" means that there is a repeating pattern -- that is, the properties repeating pattern -- that is, the properties of the elements repeat with each row -- or of the elements repeat with each row -- or period -- of the table.period -- of the table.

Amazingly, within 16 years of Mendeleev's Amazingly, within 16 years of Mendeleev's first periodic table, chemists had first periodic table, chemists had discovered all three of the missing discovered all three of the missing elements (scandium, gallium, and elements (scandium, gallium, and germanium), and their properties were germanium), and their properties were very close to what Mendeleev had very close to what Mendeleev had predicted. predicted.

Periodic TablePeriodic Table

The rows on the periodic The rows on the periodic chart are periods.chart are periods. The period tells you which The period tells you which

shell with the highest shell with the highest energy is being used by that energy is being used by that atom. So every atom in the atom. So every atom in the third period aka the third third period aka the third row is using up to the third row is using up to the third shell of their shells of shell of their shells of electrons. electrons.

Columns are groups.Columns are groups. Elements in the same Elements in the same

group have similar group have similar chemical properties.chemical properties.

Today there are 111 elements recognized by IUPAC (International Union of Pure Applied Chemistry )

GroupsGroups

These five groups are known by their names.These five groups are known by their names.

Periodic TablePeriodic Table

Nonmetals are on the Nonmetals are on the right side of the right side of the periodic table (with periodic table (with the exception of H).the exception of H).

Periodic TablePeriodic Table

Metalloids border the Metalloids border the stair-step line (with stair-step line (with the exception of Al the exception of Al and Po).and Po).

Periodic TablePeriodic Table

Metals are on the left Metals are on the left side of the chart.side of the chart.

SymbolsSymbols

All elements have All elements have their own unique their own unique symbol.symbol.

It can consist of a It can consist of a single capital letter, or single capital letter, or a capital letter and a capital letter and one or two lower case one or two lower case letters.letters.

C Carbon

CuCopper

Calculating the # of electrons in Calculating the # of electrons in each shelleach shell

In other words, electron shells have a limited capacity for In other words, electron shells have a limited capacity for electrons. electrons. 

As you might expect, the farther an electron shell is from As you might expect, the farther an electron shell is from the nucleus, the larger it is.  the nucleus, the larger it is. 

You can calculate the total capacity of an electron shell You can calculate the total capacity of an electron shell using the formula 2using the formula 2nn2, where 2, where nn equals the number of the equals the number of the electron shell.  electron shell. 

For example, for the 1st electron shell For example, for the 1st electron shell nn = 1 and 2 x 1x1 = = 1 and 2 x 1x1 = 2, telling us that the capacity of the 1st shell is 2 electrons 2, telling us that the capacity of the 1st shell is 2 electrons as we have already seen.  as we have already seen. 

For the 2nd shell (For the 2nd shell (n n = 2) and 2 x 2x2 = 8.  For an atom to = 2) and 2 x 2x2 = 8.  For an atom to fill its 2nd electron shell, it would need 10 electrons: 2 to fill fill its 2nd electron shell, it would need 10 electrons: 2 to fill the 1st shell and 8 to fill the 2nd. the 1st shell and 8 to fill the 2nd. 

The 3rd shell has a total capacity of 2 x 3x3 = 18 The 3rd shell has a total capacity of 2 x 3x3 = 18 electrons. electrons.

There are five possible shells available to atoms.  This diagram shows only three shells, and some atoms, such as the little hydrogen atom, use only the one inner shell.      Each of the elements has a different number of the tiny electrons, and a corresponding number of protons. Hydrogen is the smallest, with only one electron. Carbon, nitrogen, and oxygen, are also small, light atoms.

Shell Number

2 * (the shell number   * the shell number)

= the maximum number of electrons in this shell. 

Maximum Number of Electrons in the

Shell

1 2 x (1 x 1) = 2 2 x 1 = 2

2 2 x (2 x 2) = 8 2 x 4 = 8

3 2 x ( 3 x 3) = 18 2 x 9 = 18

4 2 x (4 x  4) = 32 2 x 16 = 32

5 2 x (5 x 5) = 50 2 x 25 = 50

Get a white piece of paper Get a white piece of paper Select 4 elementsSelect 4 elements

Draw the atomic model for eachDraw the atomic model for each

Element 5: Element 5: BoronBoronElement 6: Element 6: CarbonCarbonElement 7: Element 7: NitrogenNitrogenElement 8: Element 8: OxygenOxygen

Element 9: Element 9: FluorineFluorineElement 10: Element 10: NeonNeonElement 11: Element 11: SodiumSodiumElement 12: Element 12: MagnesiumMagnesiumElement 13: Element 13: AluminumAluminumElement 14: Element 14: SiliconSiliconElement 15: Element 15: PhosphorusPhosphorusElement 16: Element 16: SulfurSulfurElement 17: Element 17: ChlorineChlorine

Element 18: Element 18: ArgonArgon

HW choose 3 elementsHW choose 3 elements

Tell me how many protons, neutrons and Tell me how many protons, neutrons and electrons electrons

Draw a diagram of the element and color Draw a diagram of the element and color code itcode it

Valence ElectronsValence Electrons

The number of valence The number of valence electrons an atom has electrons an atom has may also appear in a may also appear in a square.square.

Valence electrons are the Valence electrons are the electrons in the outer electrons in the outer energy level of an atom.energy level of an atom.

These are the electrons These are the electrons that are transferred or that are transferred or shared when atoms bond shared when atoms bond together.together.

Valence electronsValence electrons

The outer shell electrons that are available The outer shell electrons that are available for and capable of forming bonds with for and capable of forming bonds with other atoms. Valence electrons are other atoms. Valence electrons are electrons occupying the outermost energy electrons occupying the outermost energy level.level.

Properties of MetalsProperties of Metals

Metals are good conductors Metals are good conductors of heat and electricity.of heat and electricity.

Metals are shiny.Metals are shiny. Metals are ductile (can be Metals are ductile (can be

stretched into thin wires).stretched into thin wires). Metals are malleable (can be Metals are malleable (can be

pounded into thin sheets).pounded into thin sheets). A chemical property of metal A chemical property of metal

is its reaction with water is its reaction with water which results in corrosion.which results in corrosion.

Properties of Non-MetalsProperties of Non-Metals Non-metals are poor Non-metals are poor

conductors of heat and conductors of heat and electricity.electricity.

Non-metals are not Non-metals are not ductile or malleable.ductile or malleable.

Solid non-metals are Solid non-metals are brittle and break easily.brittle and break easily.

They are dull.They are dull. Many non-metals are Many non-metals are

gases.gases.

Sulfur

Properties of MetalloidsProperties of Metalloids Metalloids (metal-like) have Metalloids (metal-like) have

properties of both metals and properties of both metals and non-metals.non-metals.

They are solids that can be They are solids that can be shiny or dull.shiny or dull.

They conduct heat and They conduct heat and electricity better than non-electricity better than non-metals but not as well as metals but not as well as metals.metals.

They are ductile and They are ductile and malleable.malleable.

Silicon

HydrogenHydrogen

The hydrogen square sits atop Family IA, The hydrogen square sits atop Family IA, but it is not a member of that family. but it is not a member of that family. Hydrogen is in a class of its own.Hydrogen is in a class of its own.

It’s a gas at room temperature.It’s a gas at room temperature. It has one proton and one electron in its one It has one proton and one electron in its one

and only energy level.and only energy level. Hydrogen only needs 1 electron to fill up its Hydrogen only needs 1 electron to fill up its

valence shell.valence shell.

Alkali MetalsAlkali Metals

The alkali family is found in The alkali family is found in the first column of the the first column of the periodic table.periodic table.

Atoms of the alkali metals Atoms of the alkali metals have a single electron in have a single electron in their outermost level, in other their outermost level, in other words, 1 valence electron.words, 1 valence electron.

They are shiny, have the They are shiny, have the consistency of clay, and are consistency of clay, and are easily cut with a knife.easily cut with a knife.

Alkali MetalsAlkali Metals

They are the most They are the most reactive metals.reactive metals.

They react violently They react violently with water.with water.

Alkali metals are Alkali metals are never found as free never found as free elements in nature. elements in nature. They are always They are always bonded with another bonded with another element.element.

What does it mean to be What does it mean to be reactive?reactive?

Elements that are reactive Elements that are reactive bond easily with other bond easily with other elements to make compounds.elements to make compounds.

Some elements are only found in nature bonded Some elements are only found in nature bonded with other elements. with other elements.

What makes an element reactive?What makes an element reactive? An incomplete valence electron level.An incomplete valence electron level. All atoms (except hydrogen) want to have 8 electrons All atoms (except hydrogen) want to have 8 electrons

in their very outermost energy level (This is called the in their very outermost energy level (This is called the rule of octet.)rule of octet.)

Atoms bond until this level is complete. Atoms with Atoms bond until this level is complete. Atoms with few valence electrons lose them during bonding. few valence electrons lose them during bonding. Atoms with 6, 7, or 8 valence electrons gain electrons Atoms with 6, 7, or 8 valence electrons gain electrons during bonding.during bonding.

IonsIons When atoms lose or gain electrons, they become When atoms lose or gain electrons, they become

ions.ions. Ions are atoms with either extra electrons or missing Ions are atoms with either extra electrons or missing

electrons. electrons. A normal atom is called a neutral atom. A normal atom is called a neutral atom. That term describes an atom with a number of That term describes an atom with a number of electrons equal to the electrons equal to the atomic numberatomic number..

If an atom has the same number of protons If an atom has the same number of protons and electrons, it is electrically neutral. If and electrons, it is electrically neutral. If electrons are added or removed, the atom electrons are added or removed, the atom (now called an (now called an ionion) becomes charged ) becomes charged

ExampleExample

Sodium (Na) atomSodium (Na) atom has eleven electronshas eleven electrons one too many in her outer shellone too many in her outer shell she needs to find another element who will take she needs to find another element who will take

that extra electron away so she can be complete that extra electron away so she can be complete (filled electrical orbital's)(filled electrical orbital's)

Bring in chlorine (Cl). Bring in chlorine (Cl). Chlorine (Cl) will take that electron away and Chlorine (Cl) will take that electron away and

leave her with 10 electrons inside of two filled leave her with 10 electrons inside of two filled shells. She is now a happy atom. shells. She is now a happy atom.

Now she is an ion and missing one Now she is an ion and missing one electron. electron.

She is now sodium ion (Na+). She has She is now sodium ion (Na+). She has one less electron than your atomic number one less electron than your atomic number

Now with filled shells. Now with filled shells. Sodium is a stable atom. LOST one (+) Sodium is a stable atom. LOST one (+)

positively charged ionpositively charged ion

Chlorine GAINED one (-) Chlorine GAINED one (-) negatively charged ionnegatively charged ion

What do you do that's so special now?What do you do that's so special now? Now that you have given up the electron, Now that you have given up the electron, you are quite electrically attractive. Other you are quite electrically attractive. Other electrically charged atoms (ions) are now electrically charged atoms (ions) are now looking at you and seeing a good partner looking at you and seeing a good partner to bond with. to bond with.

The Oppositely charged ions attract each The Oppositely charged ions attract each other and form an ionic bondother and form an ionic bond

CationsCations are positive ions and are formed by are positive ions and are formed by elements on the left side of the periodic chart.elements on the left side of the periodic chart.

Removing electrons from the atom results in a Removing electrons from the atom results in a positively charged ion, positively charged ion,

AnionsAnions are negative ions and are formed by are negative ions and are formed by elements on the right side of the periodic elements on the right side of the periodic chart.chart.

Adding electrons results in a negatively Adding electrons results in a negatively charged ion charged ion

BONDIINGBONDIING

There are two main types of bonding There are two main types of bonding ElectrovalentElectrovalent/ / Ionic Ionic and and Covalent Covalent Ionic Bonds =Ionic Bonds = the attractive force the attractive force

between oppositely charged ions that between oppositely charged ions that result from the transfer of electrons from result from the transfer of electrons from one atom to another.one atom to another.

If a compound is formed through the If a compound is formed through the transfer of electrons its called transfer of electrons its called Ionic Ionic Compound (NaCl)Compound (NaCl)

Positive because now the atom is more positively charged it has 11 protons & 10 electrons

Negative because now Cl has an extra negative charge and it will make it more negative

Covalent Bonds= Covalent Bonds= form when atoms share form when atoms share one or more pairs of electrons.one or more pairs of electrons.

The nucleus of each atom is attracted to The nucleus of each atom is attracted to the shared electrons & keeps it together the shared electrons & keeps it together

Ionic BondsIonic Bonds

Ionic compounds (such as NaCl) are Ionic compounds (such as NaCl) are generally formed between metals and generally formed between metals and nonmetals.nonmetals.

Chemical BondingChemical Bonding

Two types of bondingTwo types of bonding Ionic bondingIonic bonding Covalent bondingCovalent bonding Polar covalentPolar covalent MetallicMetallic

OPEN PPT on Desktop CHEMBONDOPEN PPT on Desktop CHEMBOND

Isotopes:Isotopes:

Atoms of the same element with Atoms of the same element with different # of different # of neutrons.neutrons.

Isotopes have different numbers of neutrons.Isotopes have different numbers of neutrons.

116C

126C

136C

146C

Some isotopes are stable, while others are radioactive—they eventually break down and release particles or energy called radiation.

Let's say an atom is missing a neutron or Let's say an atom is missing a neutron or has an extra has an extra neutronneutron. .

That type of atom is called an That type of atom is called an isotopeisotope. . An atom is still the same element if it is An atom is still the same element if it is

missing an electron. The same goes for missing an electron. The same goes for isotopes. They are still the same element. isotopes. They are still the same element. They are just a little different from every They are just a little different from every other atom of the same element. other atom of the same element.

Elements, Compounds, Elements, Compounds, MixturesMixtures

Sodium is an element.Sodium is an element. Chlorine is an element.Chlorine is an element. When sodium and When sodium and

chlorine bond they chlorine bond they make the compound make the compound sodium chloride, sodium chloride, commonly known as commonly known as table salt.table salt. Compounds have different properties

than the elements that make them up.

Table salt has different properties than sodium, an explosive metal, and chlorine, a poisonous gas.

Dalton’s PostulatesDalton’s Postulates

1. Every element is composed of tiny particles called atoms2. All atoms of a given element are identical

1. Atoms of different elements have different properties3. Atoms of an element are NOT changed into atoms of

another element by chemical processes1. Matter can neither be created nor destroyed

4. Compounds are formed when atoms of more than oneelement combine