Warm-upWarm-up

For each of the following atoms: draw For each of the following atoms: draw the Bohr model, list the # of ethe Bohr model, list the # of e-- and the and the # of valence e# of valence e--..

1.1.ClCl

2.2.PP

3.3.BeBe

4.4.SiSi

Periodic PatternsPeriodic Patterns

As a lab group, draw your assigned As a lab group, draw your assigned atoms. Then identify the pattern on atoms. Then identify the pattern on the period table.the period table.

Share the pattern with the classShare the pattern with the class Record pattern on your periodic tableRecord pattern on your periodic table

IonsIons

Ion FormationIon Formation

Elements are nonreactive if they Elements are nonreactive if they have full valence electrons shells have full valence electrons shells (like the noble gases).(like the noble gases).

They GAIN or LOSE electrons in order They GAIN or LOSE electrons in order to achieve 8 (or 2) valence electrons.to achieve 8 (or 2) valence electrons.

They will try to gain or lose the least They will try to gain or lose the least number of electrons as they can (not number of electrons as they can (not more than 3)more than 3)

ExamplesExamples

For the following atoms: For the following atoms: 1. draw the Bohr model. 1. draw the Bohr model. 2. state how many electrons it is going to gain or 2. state how many electrons it is going to gain or lose to get a full valence shelllose to get a full valence shell

– FF– SS– LiLi– MgMg– ArAr– HH– HeHe

Neutral AtomsNeutral Atoms

Have the same number of electrons Have the same number of electrons as protonsas protons

+ + + + ++ + + + +

- - - - - - - - - -

IonIon Definition: A atom (or molecule) Definition: A atom (or molecule) that has a charge (like + or 2-, etc)that has a charge (like + or 2-, etc)

Cations are Cations are PositivePositive

ExamplesExamplesNaNa++

FeFe3+3+

AlAl3+3+

MgMg2+2+

Anions are Anions are negativenegative

Examples:Examples:OO2-2-

FF--

PP3-3-

SS2-2-

Homework:Homework:

Read: 4.10 Read: 4.10 Answer: 65-73 oddAnswer: 65-73 odd

Chemical BondingChemical Bonding

Ionic BondingIonic Bonding

DefinitionsDefinitions Chemical bond: a force that holds 2 or more atoms

together making them work as a unit.

Ionic bonding: when an atom reacts with another atom, it donates or receives electrons from it (becoming IONS). They are bonded together by electrical charge (+ and -). Metal bonded with non-metal.

Covalent bonding: when atoms share electrons to complete their valence electrons. The need for a complete valence energy level covalently bonds the atoms together. Non-metal bonded with non-metal.

ReviewReview

An Atom’s electron configuration is sometimes very reactive. What determines an atom’s reactivity is how full its outer energy level is.

  If it is full, it is mostly unreactive: Ex: Noble

gases. If it is not, it can react with other atoms.

A full valence shell has 8 electrons in it. (with the exception of the first shell (2 electrons)

Lewis Dot StructuresLewis Dot Structures

A simpler version of the Bohr model that A simpler version of the Bohr model that focuses on the valence efocuses on the valence e--

Write the symbol and draw dots for each Write the symbol and draw dots for each valence evalence e-- around it. around it.

Ar F

Ca Na

Al N

Ionic BondingIonic Bonding

An atom that has less than 8 valence electrons will react to achieve a full valence shell.

It can either accept electrons or give them away

In most cases, an atom will not give or take more 3

PracticePractice

Na and Cl

Ca and S

K and O

ChargesCharges

If an atom gives away electrons it becomes + (cation)

If it takes electrons it becomes – (anion)

The attraction between the – and + charges forms an ionic bond.

Homework:Homework:

Ionic Homework Practice SheetIonic Homework Practice Sheet

Covalent BondingCovalent Bonding

Covalent bonding: when atoms share electrons to complete their valence electrons. The need for a complete valence energy level covalently bonds the atoms together. Non-metal bonded with non-metal.

Covalent BondingCovalent Bonding

Atoms will share to complete the valence shell. (8 or 2 for H/He)

  Covalent Bonds share electrons (not

give or take them)

PracticePractice

Cl + Cl 

F + F

PracticePractice

H + H  

H + H + O

HomeworkHomework

Ionic + Covalent Practice SheetIonic + Covalent Practice Sheet

Ionic Bonding Chemical Formulas: Ionic Bonding Chemical Formulas: Ions combine to form NEUTRAL Ions combine to form NEUTRAL

MOLECULESMOLECULES A molecule is a group of atoms bonded A molecule is a group of atoms bonded

together chemically.together chemically.

In order for molecules to be NEUTRAL, In order for molecules to be NEUTRAL, the charges MUST CANCEL OUT.the charges MUST CANCEL OUT.

One negative charge cancels out one One negative charge cancels out one positive chargepositive charge

Neutral MoleculesNeutral Molecules

Neutral molecules have a ZERO NET Neutral molecules have a ZERO NET CHARGE.CHARGE.

NaNa+ + + F+ F- - = NaF= NaF

MgMg+2+2 + F + F- - == MgFMgF22

To determine the To determine the chemical formula chemical formula formed from two ions (ionic bonding)formed from two ions (ionic bonding)

1.1. Find the charge that each ion tends Find the charge that each ion tends to getto get

2.2. Find the number of each cation and Find the number of each cation and anion needed to cancel out the anion needed to cancel out the charge (lowest common charge (lowest common denominator)denominator)

3.3. Combine the atoms such that there Combine the atoms such that there is an overall Zero chargeis an overall Zero charge

Ion PracticeIon Practice

For each atom write the ion it For each atom write the ion it becomes.becomes.

NaNa OO

MgMg NN

ClCl AlAl

KrKr II

A mnemonicA mnemonic SWAP AND DROP!SWAP AND DROP!

Mg+2 F-1 MgF2

Na and ONa and O

NaNa22OO

Mg and SMg and S

MgSMgS

Al and OAl and O

AlAl22OO33

B and ClB and Cl

BClBCl33

Try The following yourselfTry The following yourself

Na and SNa and S Al and IAl and I Be and OBe and O K and PK and P Ca and OCa and O Al and NAl and N

IsotopesIsotopes Isotopes of MagnesiumIsotopes of Magnesium

1.1. Protons: 12, Neutrons: 12, Mass: 24Protons: 12, Neutrons: 12, Mass: 242.2. Protons: 12, Neutrons: 12, Mass: 24Protons: 12, Neutrons: 12, Mass: 243.3. Protons: 12, Neutrons: 12, Mass: 24Protons: 12, Neutrons: 12, Mass: 244.4. Protons: 12, Neutrons: 12, Mass: 24Protons: 12, Neutrons: 12, Mass: 245.5. Protons: 12, Neutrons: 12, Mass: 24Protons: 12, Neutrons: 12, Mass: 246.6. Protons: 12, Neutrons: 12, Mass: 24Protons: 12, Neutrons: 12, Mass: 247.7. Protons: 12, Neutrons: 12, Mass: 24Protons: 12, Neutrons: 12, Mass: 248.8. Protons: 12, Neutrons: 12, Mass: 24Protons: 12, Neutrons: 12, Mass: 249.9. Protons: 12, Neutrons: 13, Mass: 25Protons: 12, Neutrons: 13, Mass: 2510.10.Protons: 12, Neutrons: 14, Mass: 26Protons: 12, Neutrons: 14, Mass: 26

Step for calculating the atomic Step for calculating the atomic massmass

Requirements: list of Isotopes and % of Requirements: list of Isotopes and % of each isotope.each isotope.

1.1.Convert each percent to a decimal Convert each percent to a decimal (by dividing by 100 and removing %)(by dividing by 100 and removing %)

2.2.Multiply each isotope by its “percent Multiply each isotope by its “percent as a decimal”as a decimal”

3.3.Add all the isotope answers from #2Add all the isotope answers from #2

Atomic Mass PracticeAtomic Mass Practice

Element Mr has the following Element Mr has the following percentages of different isotopes:percentages of different isotopes:

5656Mr =71.2%Mr =71.2%5454Mr =20.3%Mr =20.3%5757Mr =8.5%Mr =8.5%

What is Mr’s atomic mass?What is Mr’s atomic mass?

More PracticeMore Practice

Element Lh has the following Element Lh has the following percentages of different isotopes:percentages of different isotopes:

1111Lh =19%Lh =19%1212Lh =21%Lh =21%1313Lh =27%Lh =27%1414Lh =33%Lh =33%

What is Lh’s atomic mass?What is Lh’s atomic mass?

Molecule Game!Molecule Game! You will receive a few pieces of paper with an You will receive a few pieces of paper with an

element on it. Your first job is to determine what element on it. Your first job is to determine what each element’s charge is. DO NOT WRITE THE each element’s charge is. DO NOT WRITE THE CHARGE ON THE PAPER!CHARGE ON THE PAPER!

You will then use ONE of your elements to join You will then use ONE of your elements to join with some other folks to make a Neutral Molecule.with some other folks to make a Neutral Molecule.

Rules:Rules:– There can only be 2 different elements in your molecule There can only be 2 different elements in your molecule

(for example, can’t have B Na AND F)(for example, can’t have B Na AND F)– Your Molecule MUST be neutral based on the number of Your Molecule MUST be neutral based on the number of

each atomeach atom– You can only use one of the elements you are given…not You can only use one of the elements you are given…not

both.both.– When time is called, Ms. Tetler will check to make sure When time is called, Ms. Tetler will check to make sure

you have a neutral molecule.you have a neutral molecule.