Metals vs. Non-Metals; Dot Diagrams; Ionsrgollahon.weebly.com/uploads/1/6/3/6/16361290/... · metals and non-metals because metals become cations (positive ions) and non-metals become

Ch. 19:1 Name: _____________________

Period:_____________________

Copyright © 2003, C. Stephen Murray

Metals vs. Non-Metals; Dot Diagrams; Ions

Metals versus Non-Metals

Dot Diagrams

Metals are on the left side. Non-metals on the right. Metals tend to lose electrons. Non-metals gain them tight.

Dot Diagrams (sometimes known as Lewis dot diagrams) are a depiction of an atom’s valence electrons. They are a powerful tool in helping you understand, see, and even predict molecular bonding.

Ne 1

2

5

4

6

8

3

7

Put the correct number of valence electrons around the chemical symbol in this order in pairs:

Neon has 8 valence electrons (in the right hand column). Neon has no unoccupied spaces. It is full.

Li Lithium, with 1 valence electron (first column).

O Oxygen has 6 valence electrons. How many more before it’s full?

______.

Draw the Dot Diagrams for the following elements:

Beryllium Carbon Helium Sodium Boron

The dividing line is the red or bold black line from between Boron and Aluminum down and to the right. Everything to the left is a metal: to the right, non-metal. One exception (don’t ya just hate that?!) is hydrogen – a non-metal. Sodium (Na) is a metal. Oxygen is a non-metal.

1 H

3 Li

19 K

11 Na

4 Be

20 Ca

12 Mg

5 B

31 Ga

13 Al

6 C

32 Ge

14 Si

7 N

33 As

15 P

8 O

34 Se

16 S

9 F

35 Br

17 Cl

2 He

10 Ne

36 Kr

18 Ar

Metals

Non-Metals Dividing

line

Non-metal (exception)

Easy to remember by which side iron (Fe) is on—the left side!

Potassium: __________

Bromine:____________

Beryllium: __________

Helium:_____________

Fluorine: ____________

Hydrogen ___________

Silver_______________

Nitrogen ____________

Metal or Non-metal?

On either side of the divide are the metalloids or semi-metals—they have characteristics of both: B, Si, Ge, As.

Why would the electrons spread out around the atom instead of bunching up?

Notice that the electrons are in pairs not a circle.

C Carbon has 4 valence electrons

Ch. 19:1 Name: _____________________

Period:_____________________


Ions If you change the number of protons you change the element. If you change the number of neutrons you change the isotope. If you change the number of electrons you change the ion.

3p 3n

Lithium Li

3 protons (+3) 3 electrons (-3)

+3 –3 = 0 Neutral atom!

Neutral atoms have an equal number of protons and electrons. A neutral atom has a net electrical charge of zero.

3p 3n

Lithium Li 1+

3 protons (+3) 2 electrons (-2)

+3 –2 = +1 positive ion!

Loses an electron

An ion is an atom with a net charge; that has gained or lost electrons. Why would atoms gain or lose

electrons? To fulfill the octet rule and end up with a full outer shell of electrons. Metals will lose electrons and make positive ions (cations); non-metals will gain electrons and make negative ions (anions).

Cations cough up electrons - Lose electrons (+ ion). METALS Anions accept electrons - Gain electrons (- ion). NON-METALS

If Oxygen gains 2 electrons what charge will it have?

If Beryllium loses 2 electrons what charge will it have?

What is the charge of an atom with 16 protons and 18 electrons?

Protons – electrons = ion charge OR p – e = charge

Ion Notation

Na 1+ Chemical symbol

Charge (1 electron lost)

Ex. How many electrons does Mg 2+ have?

p - e = charge 12 (Mg) - e = +2

12 = 2 + e 12—2 = e

e = 10 electrons

You also could have found this by knowing Mg has 12 protons and electrons if neutral. A 2+ charge

means it is a cation—it lost 2 electrons = 12—2 = 10 electrons.

How many electrons does Cl 1– have? How many electrons does Al 3+ How many electrons does N 3– have?

Give the ion notation for an atom with 20 protons and 18 electrons.



Ch. 19:2 Name: _____________________

Period:_____________________


Bonding

Chemical Bonding Why haven’t you grown up recognizing all of the elements around you? Because most substances are compounds. Very few elements are stable enough to exist pure. Instead they react with other elements to form compounds. Why?...

Octet Rule—atoms strive to achieve a full set of valence electrons. This is usually 8 (what are the exceptions). Atoms are more stable with a full outer shell.

To fulfill the octet rule atoms will lose, gain, or share electrons. Atoms will get 8 valence electrons the fast-est way: metals will lose electrons; non-metals will gain electrons.

Why? Having a few more protons more than closest noble gas, metals have too much shielding—the electrons don’t fell much attraction to the nucleus. Non-metal have more protons and can attract more electrons to the energy level.

Ionic Bonds—Bonds of attraction

Na

By itself sodium is very reactive (it will explode

in water).

So it loses one electron.

Na1+

Now, it has a full set of 8 outer electrons. It becomes a positive ion (a cation).

Chlorine (a poisonous gas) has 7 valence

electrons so it needs one more to be stable.

So it gains one electron.

Now, it has a full set of 8 outer electrons. It is a ion with a 1+ charge (a cation).

Cl Cl 1-

Na1+ Cl1- And opposites attract

NaCl

To form a stable

compound. Sodium Chloride —Table salt.

Ionic bonds occur between metal and non-metal ions.

Will these ions make compounds?

K and Li? ___________ Be and Cl? __________

Al and F ? ___________ Fe and O? ___________

Ion Notation Review Ion—a non-neutral atom (different number of protons and electrons). To find charge or number of electrons, use: protons—electrons = charge OR p - e = charge

Mg 2+ Chemical symbol

Charge (2 electrons lost)

Cations — positive ions (metals); Losers of electrons. Anions — negative ions (non-metals); Gainers of electrons.


Mg 2+ and Li 1+? ___________ Na 1+ and O 2- ?____________

Ca 2+ and F 1- ? ____________ O 2- and Cl 1- ?_____________

Will these elements make ionic compounds?

Give the ion notation for Sulfur with 18 electrons.

What force will the two above ions feel?

Why?

Ch. 19:2 Name: _____________________

Period:_____________________


1. Ca 2+ O 2- 2. Ca 2+ O 2-

3. CaO

(2s reduce)

Sometimes there are no opposites around to form ionic bonds (Oh, NO!), but atoms will still find a way to get to that full shell of 8 valence electrons. So instead of gaining extra electrons they SHARE THEM. This is called a COVALENT BOND.

Cl Cl

Sharing one electron each

Cl Cl

Covalent Bonds—Cooperative Bonding Covalent bonds happen between two non-metals.

Ionic or covalent bonds?

MgO ____________ CO2 _____________

PO5 ______________ BeF2 _____________

CaO _____________ SO2 _____________

Cl—Cl

Short cut notation for a single bond.

Sharing 2 electrons each

O O O O

Each oxygen needs 2 more electrons.

O O Short cut notation for a double bond.

Draw the covalent bond between 2 Nitrogens:

Draw the covalent bond between 2 Fluorines:

Oxidation Numbers The ions charges that atoms gain when they lose or gain their valence electrons are the number of electrons they can gain or lose when bonding. We call these Oxidation Numbers.

1 H

3 Li

19 K

11 Na

4 Be

20 Ca

12 Mg

Transition Metals

5 B

31 Ga

13 Al

6 C

32 Ge

14 Si

7 N

33 As

15 P

8 O

34 Se

16 S

9 F

35 Br

17 Cl

2 He

10 Ne

36 Kr

18 Ar

Oxidation Numbers 1

2 3- 43

0

2- 1-

Find the Oxidation Numbers for the following:

Be ___________

O ___________

Cl ___________

N ____________

Li ___________

H ____________

He ___________

Al ___________

P ____________

Ar ___________

Making Ionic Compounds You can figure out how to make stable ionic compounds from the oxidation numbers. Lithium (1+) can give 1 electron; Oxygen (2-) needs 2 to be full. So Oxygen needs 2 Lithiums to balance as a compound.

Li1+ O 2-

Li2O

1

23

Li1+ O 2- 2

1

Write the chemical symbols with the oxidation numbers.

Cross the numbers not the signs.

Reduce numbers or drop ones.

Ex. Make a balanced ionic compound of Calcium and Oxygen.

Chemical symbols and oxidation numbers. Cross the numbers not the signs Reduce numbers and drop ones.

2 2

Make ionic compounds from:

Na and S: Al and Cl:

Ch. 19:3 Name: _____________________

Period:_____________________


More Chemical Bonding

Bonding Review Most elements react to form compounds. Elements do this to gain a full set of valence electrons (Octet Rule— “If I 8 I full”).

Ionic Compounds occur between metals and non-metals because metals become cations (positive ions) and non-metals become anions (negative ions). And opposites attract.

Polyatomic Compounds are compounds with 3 or more elements. These are just large ionic compounds. They happen because sometimes when two elements react they don’t fulfill the octet rule and end up with a net electrical charge.

Ionic, Covalent, or Polyatomic?

K2O ___________________ (Potassium oxide) CO2 ___________________ (Carbon dioxide)

AlF3 __________________ (Aluminum fluoride) MgCO3 ________________ (Magnesium carbonate)

Li2CrO4 ________________ (Lithium chromate) SiCl4 __________________ (Silicon tetrachloride)

Ca3N2__________________ (Calcium nitride) NaCl __________________ (Sodium chloride—table salt)

Covalent Compounds occur between non-metals. Because neither element will give up their electrons (too many protons), they share electrons to com-plete the full set of 8.

Be2+ Cl1- Opposites attract

O O O O

Oxygens sharing to gain 8 electrons each

4 shared electrons (2 from each)

Mg2+ NO3-

Big opposites attract, too

BeCl2 Beryllium Chloride

Mg(NO3)2 Magnesium nitrate O O Short cut notation

for a double bond.

Cross the number not the sign to get:

Making Ionic Compounds

Na Cl

Use dot diagrams like puzzle pieces. For ionic compounds remember

that the metal is actually losing the electron to the non-metal.

Na Cl

Or use the “cross the number not the sign” method:

Ca2+ Cl1- 1

2

This compound will be stable because the net charge is zero.

1(2) + 2(-1) = 2 - 2 = 0

Ionic compounds are balanced if the net charge is zero. Use this formula:

Oxidation numbers of ion 1 and 2

Number of atoms of element 1 and 2

O1(N1) + O2(N2) = CN

Net charge - if zero, then it is an ionic compound

Li and N

Ca and O

Al and Cl

Na and Ne

Make Balanced Ionic Compounds Using the formula above show that Na2O is balanced.

Ch. 19:3 Name: _____________________

Period:_____________________


O

Carbon has only 6

Seeing how covalent bonds connect together is easy for single bonds, like chlorine. Yet it can be hard to see for triple bonds like Nitrogen. For compounds it can get even more difficult.

Cl Cl

Sharing one electron each

Cl Cl

Covalent Bonds—Diatomic Molecules Diatomic molecules have 2 atoms of

the same element. N, O, F, Cl

Cl—Cl

Short cut notation for a single bond.

Sharing 2 electrons each

O O O

Each oxygen needs 2 more electrons.

O O Short cut notation for a double bond.

Each line stands for a shared pair of electrons: 1 from each Draw the covalent bond between two Bromine

atoms:

Covalent Compounds

Two Tricks— 1) If you cover one of the atoms up with a piece of paper (or a finger) you can see if the other atom has the necessary 8 electrons. 2) The number of extra electrons you need to make 8 goes on the sharing side of the chemical symbol. Ex. Nitrogen has 5 valence electrons and needs 3 more to be full, so put 3 electrons on the side toward the other N.

Draw the covalent bond between two Fluorine atoms:

When trying to figure out covalent compounds, it may take some time and creativity. Remember to look at the atoms as puzzle pieces.

Cl

Ex. Make Sulfur Dichloride (SCl2)

Cl

Tip: it can help to draw the electrons differently (like x’s and o’s) for the different elements. This can help you keep track from where the electrons came.

6 valence electrons

7 valence electrons

Move them around until each atom has 8 electrons by sharing.

Short hand notation

Cl S Cl

Each bar is a shared electron pair

S

Make Carbon monoxide (CO)

O C Oxygen needs 2 more electrons, but carbon needs 4. Either oxygen will have too many, or carbon will have too few.

O C This is why CO is an unstable, poisonous compound! It will react with oxygen in your body to form CO2 and could kill you!

Draw the covalent compound of CO2:

Draw the covalent compound of NF3:

Draw the covalent compound of CH4 (methane):

Cl

Cl S

Ch. 19:4 Name: _____________________

Period:_____________________

Copyright © 2003, C. Stephen Murray www.aisd.net/smurray

Naming Compounds

What’s it Made of?

Metal and non-metal

2 non-metals

3 or more elements

polyatomic compound

covalent compound

ionic compound

USE “- IDE” ENDING (NO PREFIXES!)

Name the metal and non-metal and change the ending to “ide”.

USE GREEK PREFIXES

Put prefixes in front of element names to tell how many atoms are there.

Don’t use “mono” for first name,

but always for second name.

CHECK THE CHART BELOW (NO PREFIXES!)

Use the names on the chart.

If the polyatomic ion is the cation end the second name with “-ide”.

Li2S

Metal and non-metal— ionic

Lithium Sulfide

(not dilithium sulfide— no prefixes for ionic compounds)

N2O4

2 non-metals—covalent

(di =2 and tetra =4)

“Dinitrogen tetroxide”

NaNO3

3 elements — polyatomic

Check chart (see below) Na - sodium

NO3 - nitrate (on chart)

Sodium nitrate

Polyatomic Ions

Oxidation # Name Formula

1+ ammonium NH4+

1- acetate C2H3O2-

2- carbonate CO32-

2- chromate CrO42-

1- hydrogen carbonate

HCO31-

1+ hydronium H3O+

1- hydroxide OH1-

1- nitrate NO31-

2- peroxide O22-

3- phosphate PO43-

2- sulfate SO42-

2- sulfite SO32-

Greek Prefixes

Mono - 1

Di – 2 Tri – 3

Tetra – 4 Penta – 5

Hexa – 6 Hepta – 7 Octa – 8 Nona – 9 Deca – 10

Exception— O2 is “peroxide” and can make polyatomic com-pounds with only 2 ele-

ments! O2 with a non-metal is dioxide. O2 with a metal OR Hydrogen (acting as a

metal) is peroxide.

Why are ionic compounds so easy to name? Because most ionic com-

pounds can only form one way, using the oxidation numbers. In covalent compounds, though, non-metals can sometimes combine in multiple ways (carbon monoxide; carbon dioxide).

So, covalent compounds use prefixes.

How to remember prefixes:

Monorail – one rail train Monocle – glasses for one eye;

single lens (Colonel Klink). Dilemma – struggle between 2 choices. Tricycle – 3 wheels

Pentagon – 5 five sided military building in Washington, D.C.

Octopus – 8 legs Decade – 10 years

Transition Metals Can Have More Than One Oxidation Number

Iron (II) has an oxidation number of 2+

Iron (III) has an oxidation number of 3+. When naming them you must specify

WHICH ONE.

FeO—Iron (II) oxide Fe2O3— Iron (III) oxide

How to use this chart— Determine what the

compound is made of and follow the arrows. The

chart will tell you how to name the compound.

Ch. 19:4 Name: _____________________

Period:_____________________


Use the Polyatomic Ion Chart on the front of the worksheet to name these Polyatomic Ions:

HCO31-

SO42-

O22-

SO32-

NO31-

NH4+

CrO42-

OH1-

PO43-

CO32-

Hydrogen carbonate

___________________

___________________

___________________

___________________

___________________

___________________

___________________

___________________

___________________

Metal or Non-metal?

Ionic or Covalent?

Iron Oxide Ionic Barium Chloride ____________ Carbon Dioxide ____________ Magnesium Oxide ____________ Aluminum Fluoride ____________ Nitrogen Tribromide ____________ Chromium Fluoride ____________ Potassium Oxide ____________

M N

Name These Ionic Compounds

MgF2 Magnesium Fluor-ide

Li2O Lithium Ox- __________________

NaCl Sodium Chlor- ________________

K2O Potassium Ox-_________________

CaS _______________ Sulf- _________

BeI2 _______________ Iod-__________

AlBr3 _______________ Brom-________

CaF2 ____________________________

MgO ____________________________

LiCl ____________________________

Classify and Name These Compounds

1. BaCl2 Ionic __ Barium chloride _

2. CO _____________ _______________________________

3. Ag2O _____________ _______________________________

4. K2SO4 _____________ _______________________________

5. MgBr2 _____________ _______________________________

6. SO3 _____________ _______________________________

7. P2O4 _____________ _______________________________

8. Be(CrO4) _____________ _______________________________

9. LiF _____________ _______________________________

11. CO2 _____________ _______________________________

12. OF2 _____________ _______________________________

Ionic, Covalent, or Polyatomic Name

Define these Greek Prefixes

Penta = ______ Nona = ______ Mono = ______ Octa = ______ Tri = ______

Tetra = ______ Hexa = ______ Hepta = ______ Deca = ______

Di = ______

1. CO2

2. C2O4

3. C3O5

4. CO

5. C2O

6. CO8

A. Carbon monoxide

B. Carbon dioxide

C. Dicarbon monoxide

D. Tricarbon pentoxide

E. Dicarbon tetroxide

F. Carbon octoxide

Si2O3 Disilicon _____oxide

N3Cl4 _____nitrogen tetrachloride

SO2 Sulfur _____oxide

PO5 Phosphorous ______ox____

S2F4 ____sulfur _____fluor____

Name These Covalent Compounds

Name these Polyatomic Compounds (Remember — no prefixes!)

CaSO4 Calcium _________________

K2CO3 ________________ carbonate

CuNO3 Copper (I) ________________

NH4Cl _________________ chloride

Mg(NO3)2 Magnesium _______________

K3PO4 Potassium _________________

Li2(CrO4) Lithium _____________________

Mg(OH)2 M___________ H_____________

Al(PO4) A______________ P___________

K(NO3) _____________ ______________

Ca2SO3 _____________ ______________

Ch. 19:5 Name: _____________________

Period:_____________________


Naming and Covalent Compounds

Making Ionic Compounds

Ion Notation Na 1+

How many protons and electrons does S 2– have?

Give the ion notation for Calcium that lost 2 electrons.

How many electrons does K 1+ have?



Fe3+ :did it gain or lose electrons and how many?

Find from number of protons Find from p-e=charge OR Number of electrons: (+) lost or (-) gained.

Tells you: sodium (11 protons) and 1 electron lost (+), so only 10 electrons.

Li1+ O 2-

Li2O

1

23

Li1+ O 2- 2

1


Cross the numbers not the signs.

Reduce numbers or drop ones and put the symbols together.

Way 1

Mg2+ Cl1-

MgCl2

1.

2.

3.

Mg2+ Cl1-


Add enough ions together so that the charges equal zero.

Add up the ions and write the compound as a formula.

Way 2

Cl1-

You know it is a balanced compound because 2(1) + 1(-2) = 0. Balanced ionic compounds have a neutral charge.

Again, you know it is a balanced compound because 1(2) + 2(-1) = 0. Balanced ionic compounds have a neutral charge.

Make the ionic compound of magnesium oxide.

Combine Fe(II) and O. Make lithium chloride.

Combine Iron(III) and Fluorine. Make potassium sulfate (SO42-). Combine sodium and carbonate (CO3)2-.

Ch. 19:5 Name: _____________________

Period:_____________________


Covalent Bonding You must fulfill two criteria when making covalent bonds: 1) the individual atoms must have the proper number of valence electrons; 2) when bonded each atom must have 8 electrons through sharing.

Each has 6 valence electrons by itself and 8 by sharing.

O

Put the number you need in the middle to share.

O O A double covalent bond.

Read each oxygen as 6 v.e. plus 2 for the 2 bonds = 8!

O 8 8

O O 6 6

Oxygen dichloride: OCl2

6 v.e. 8 shared O Cl

Cl 7 v.e.

8 shared

7 v.e. 8 shared

Make F2. Make N2. Make S2.

Make oxygen difluoride: OF2 Make methane: CH4. Make carbon dioxide: CO2

Naming Compounds

Ionic compounds (metals and non-metals): Name the metal and non-metal and change the ending to “-ide”.

BeO: Beryllium oxide MgCl2: Magnesium chloride.

Covalent compounds (2 non-metals): Use the prefixes to show how many atoms are there.

CO: Carbon monoxide CO2: Carbon dioxide.

Polyatomic compounds (3 or more elements): Use the names on the polyatomic ion chart.

Al(PO4): Aluminum phosphate Be(CrO4): Beryllium chromate.

1. NF3 ___________________________________

2. FeO ___________________________________

3. Na2SO3 ___________________________________

4. LiBr2 ___________________________________

5. O2Cl4 ___________________________________

6. CS2 ___________________________________

7. Ca3P2 ___________________________________

8. NaCl ___________________________________

9. LiOH ___________________________________

10. N2F3 ___________________________________

O Cl

Cl

Short hand

Ch. 19:6 Name: _____________________

Period:_____________________


Naming and Covalent Compounds

Naming

1. MgCl2 Ionic Magnesium chloride _______

2. PF3 ______ _____________________________________

3. CaO ______ _____________________________________

4. K3(PO4)2 ______ _____________________________________

5. MgCl2 ______ _____________________________________

6. CO ______ _____________________________________

7. S2O4 ______ _____________________________________

8. Mg(CrO4) ______ _____________________________________

9. NaF ______ _____________________________________

10. H2O ______ _____________________________________

11. CO2 ______ _____________________________________

12. OBr2 ______ _____________________________________

Type: Ionic; Covalent; Polyatomic.

Compound Name

Polyatomic Ions Oxidation # Name Formula

1+ ammonium NH4+

1- acetate C2H3O21-

2- carbonate CO32-

2- chromate CrO42-

1- hydrogen carbonate

HCO31-

1+ hydronium H3O1+

1- hydroxide OH1-

1- nitrate NO31-

2- peroxide O22-

3- phosphate PO43-

2- sulfate SO42-

2- sulfite SO32-

Use only for Polyatomic Compounds

Greek Prefixes

Mono - 1

Di – 2 Tri – 3

Tetra – 4 Penta – 5

Hexa – 6 Hepta – 7 Octa – 8 Nona – 9 Deca – 10

Use only for Covalent Compounds

Ch. 19:6 Name: _____________________

Period:_____________________


Covalent Bonding You must fulfill two criteria when making covalent bonds: 1) the individual atoms must have the proper number of valence electrons; 2) when bonded each atom must have 8 electrons through sharing.

How many protons and electrons does O 2– have? Is it a metal or non-metal?

Give the ion notation for Calcium that lost 2 electrons. Cation or anion?

How many electrons does K 1+ have? Is it a cation or an anion?

Make the ionic compound of Lithium oxide.

Combine Sodium and phosphate (PO4)3- Make Iron (III) chloride.

Each has 6 valence electrons by itself and 8 by sharing.

O

Put the number you need in the middle to share.

O O A double covalent bond.

Read each oxygen as 6 v.e. plus 2 for the 2 bonds = 8!

O 8 8

O O 6 6

Oxygen dichloride: OCl2

6 v.e. 8 shared O Cl

Cl 7 v.e.

8 shared

7 v.e. 8 shared

Make Cl2. Make P2. Make O2.

Make Sulfur difluoride: SF2 Make water. Make sulfur dioxide: SO2

Reviewing

O Cl

Cl

Short hand

Start getting ready for the test. Know: valence electrons; oxidation numbers; metals vs. non-metals; dot diagrams; ion no-tation; cation versus anion; differences between ionic, covalent and polyatomic com-pounds; how to name compounds; how to make ionic compounds; how to make covalent compounds.

Documents

Metals vs. Non-Metals; Dot Diagrams; Ionsrgollahon.weebly.com/uploads/1/6/3/6/16361290/... · metals and non-metals because metals become cations (positive ions) and non-metals become