Atoms, Molecules and Ions Chapter 2 (p.49-68)

Chapter 2

Atoms, Molecules and Ions

CHAPTER 2 (P.49-68)

• Atomic number , mass number and isotopes.

• The periodic table .

• Molecules and ions .

• Chemical formulas .

• Naming compounds

Atomic Structure

Elements: are composed of extremely small particles called atoms.

ضِرْلأَا يفِ لاَوَ تِاوَامَ سَّلا يفِ #ةٍ رْذَ &لُاقَثْمِ &هُنْعَ &بُ &زُعْيَ لاَ{

:أبس( } #نٍيب:مِ #بُاتَكِ يفِ لاَإِ &رُبكِأَ لاَوَ كَلذَ نٍمِ &رُغَصْأَ لاَوَ

3 .)

Atom: is the basic unit of an element that can enter into chemical combination

Atom consists of:

Electron (e) (-ve charge) Proton (p) (+ve charge) Neutron (n) (neutral)

Subatomic Particles

mass p = mass n = 1840 x mass e

^-

2.2

2.3 Atomic number , mass number

and isotopes.

Atomic number (Z) = number of protons in nucleus.

A

X

Z

1

H

1 ¹²₆

C

⁸³₃₆

Kr

Mass Number

Atomic Number Element Symbol

2.3

In the neutral atom: the No. of protons is equal the No. of electrons .

So the atomic number also= No. of electrons .

Mass number (A) = number of protons + number of neutrons = atomic number (Z) + number of neutron

No. of neutron= mass No. (A)- atomic No. (Z)

4

He

2

Examples :

elements

Atomic Number (Z) 11 11 8 6 80

Mass Number (A) 20 22 17 14 200

No. of electrons (e) 11 11 8 6 80

No. of protons (p) 11 11 8 6 80

No. of neutrons (n) 9 11 9 8 120

Give the number of protons, neutrons, and electrons in each of the following species:

Example 2.1

20Na

11 ²²Na

11 ¹⁷O

8 ¹⁴C

6 ²⁰⁰Hg

80

Define the element ⁶³₂₉X?

The element with atomic number 29 is cupper (Cu) and its mass number is 63

6 protons, 8 =(14 - 6) neutrons, 6 electrons

Do You Understand Isotopes?

How many protons, neutrons, and electrons are in ¹⁴₆C ?

How many protons, neutrons, and electrons are in ¹¹₆C ? 6 protons, 5 =(11 - 6) neutrons, 6 electrons

Isotopes are atoms of the same element (X) with different numbers of neutrons in their nuclei

1

H

1 ²₁

H (D)

³₁

H (T)

235

U

92 ²³⁸₉₂

U

12

C

6 ¹³₆

C

¹⁴₆

C

examples :

Isotopes of an atom have essentially the same chemical behavior .

1 P 1 P 1 P 0 n 1 n 2n

Isotopes of Hydrogen

12

C

6 ¹³₆

C

¹⁴₆

C

Isotopes of an atom have essentially the same chemical behavior .

235

U

92 ²³⁸₉₂

U

uranium-235 uranium-238

Practice Exercise:

How many protons, neutrons, and electrons are in the following isotopes

Practice Exercise:

How many protons, neutrons, and electrons are in the following isotope of copper: ⁶³Cu?

How can I get the atomic number: look at the periodic table

→ then find the number of p, n & e.

63

Cu

29

P=29 n=34

e=29

Allotrope is one of tow or more distinct forms of an element as O₂ , O₃ .

Allotropes

O-O (O₂) and O₃

Allotropes are different structural forms of the same element and can exhibit quite different physical properties and chemical behaviors.

Allotropes

Graphite Diamond

the carbon atoms are bonded together in sheets of a

hexagonal lattice arrangement.

the carbon atoms are bonded together in a tetrahedral lattice arrangement.

allotropes of an element differ on the structure of the same atoms, (i.e. how the atoms are arranged).

isotopes of the element differ on the number of

neutrons of the atoms (i.e. the composition of subatomic particles in an atom).

The Difference between Allotropes and Isotopes

2.4 The periodic table

Period

Group

Alkali Metal Noble Gases

Halogen

Alkaline Earth Metal

2.4

Periodic Table

The periodic Table: is a chart in which elements having similar chemical and physical properties are grouped

together.

The elements in the modern periodic table are arranged by

atomic number

Metal

Metalloid Nonmetal

.

.

.

• Positive ions are called:

a. positrons.

b. anions.

c. cations.

d. nucleons.

• The elements located in group 7A of the periodic table are called:

a. alkali metals.

b. noble gases.

c. chalcogens.

d. halogens.

What are the ions present in the compound (NH₄)₂SO₄ ?

 NH₃, H₂, and SO₂

 N^3–, H⁺, S^2–, O^2–

 NH₄²⁺ and SO₄^–

 NH₄⁺ and SO₄^2– (3 IONS)

 (NH₄⁺)₂ and SO₄^2–

1- Selenium (₃₄Se) element is:

(a) a nonmetal

(b) found in group 6A (c) both a and b

2- Gallium (Ga) element is found in the periodic table in

(a) period 3, group 1B (b) period 3A, group 4 (c) period 4, group 1A (d) period 4, group 3A

3- Which of the following sets of

elements is expected to have similar chemical properties?

a) Sulfur and phosphorous b) Sulfur and oxygen

c) Sulfur and argon

4- Which of these elements is most likely to be a good conductor of

electricity? 

Which of the following is metal?

A. N

B. S

C. He

D. Fe

Chemistry In Action

Natural abundance of elements in Earth’s crust

Natural abundance of elements in human body

2.4

2.5 MOLECULES AND IONS.

H₂ H₂O NH₃ CH₄

The monatomic gases are the single atoms of noble gases; He, Ne, Ar, Kr, Xe, Rn.

A molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical forces.

Diatomic molecule: contains only two atoms

H₂, N₂, O₂, Br₂, HCl, CO, NO, KCl

Polyatomic molecule:

contains more than two atoms

O₃, H₂O, NH₃, CH_{4 ,}NaOH

Molecule

Cation

an ion with a +ve charge (lose electron/s)

Na⁺, K⁺, Mg²⁺

Al^3+, N^3-

Anion

an ion with a -ve charge ( Gain electron/s)

Ion

Monoatomic cation Polyatomic cation Monoatomic anion Cl^-, Br^-,S^2-

Polyatomic anion OH^-, PO₄^3-

NH₄⁺

Ion

is an atom, or group of atoms, that has a net positive or negative charge.

• Which of the following is an example of

polyatomic cation?

• A) Mg⁺²

• B) NH₄⁺¹

• C)O^-2

• D) SO₄^-2

• Which of the following is an example of monatomic anion?

• A) Mg⁺²

• B) NH₄⁺¹

• C)O^-2

• D) SO₄^-2

11Na _electrons^{protons 11}₁₁ ⁺₁₁Na _electrons^{protons 11}₁₀

17Cl _electrons^{protons 17}₁₇ ^-17Cl _electrons^{protons 17}₁₈

Cation

anion

11Na _electrons^{protons 11}₁₁ ⁺₁₁Na _electrons^{protons 11}₁₀

17Cl _electrons^{protons 17}₁₇ ^-17Cl _electrons^{protons 17}₁₈

Cation

anion

13 protons, 10 (13 – 3) electrons

34 protons, 36 (34 + 2) electrons

Do You Understand Ions?

How many protons and electrons are in ?₁₃²⁷Al ³⁺

How many protons and electrons are in ?⁷⁸₃₄Se^2-

 3 27

13 Al

 2 78

34

Se

2.5

Different Ions of Some Elements

Metals tend to form cations

Nonmetals tend to form anions

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

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

Metals are on the left side of the chart (green color)

31P

15 3- 11B

5 196^Au

79 222^Rn 86

26 54-26=28

26-2=24 2+

0 0

18- 3=15

86

2.6 CHEMICAL FORMULAS.

2.6

ةغَيصلا ةيئيَزُجلا

ةغَيصلا ةيئانْبلا

جذَومَن ةٍرُكلا اصعْلاوَ

جذَومَن ءلمِ

غارُفلا

A molecular formula shows the exact number of atoms of each element in the smallest unit of a substance

An empirical formula shows the simplest whole-number ratio of the atoms in a substance

H₂O H₂O

molecular empirical

C₆H₁₂O₆ CH₂O

O₃ O

N₂H₄ NH₂

ةيلوَلأَا ةغَيصلا ئزُجلل ةٍرْوصْ طسَّبأَ

دوجوَ بسَّن يطعْت ئزُجلل ةنوكمَلا تِارْذلا نٍمِ سيلوَ ةبسَّن رُغَصْأب

يطعْت نأَ يرْوَرُضلا تِارْذلل حيحصلا ددعْلا

ةيئيَزُجلا ةغَيصلا

حيحصلا ددعْلا ىلعَ يوتَحت لخديَ رُصنْعَ لكِ تِارْذَ نٍمِ

هدحوَ رُغَصْأَ بيكِرُت يفِ

)ئزُجلا( ةٍدامَلا يفِ

ةيئيَزُجلا ةغَيصلا نٍمِ

ةغَيصلا داجيَإِ عيطتَسَّن رُيغ سكعْلاوَ ةيلوَلأَا

حيحصْ

• The Empirical Formula may the same or different from the Molecular Formula

• How can we get the Empirical Formula?

• Answer: Divide all the numbers by the largest Common devisor.

• e.g. The empirical formula of H₂O is H₂O

• e.g. the empirical formula of C₆H₁₂O₆ is CH₂O (divide the numbers 6, 12 and 6 by the largest common devisor 6)

It must be noted that :

• Write the Empirical formulas for the following molecules

 Acetylene C₂H₂ divided by 2 CH

 Glucose C₆H₁₂O₆ divided by 6 CH₂O

 Nitrous oxide N₂O , the Empirical formulas is same as molecular formula N₂O

 Caffeine C₈H₁₀N₄O₂ divided by 2 C₄H₅N₂O

EXAMPLE 2.3

Examples

• Which of the following is empirical formula

A. O3 >>>>>> O B. H₂SO₄ C. S8 >>>>>>> S

D. C₆H₁₂O6 >>>> CH₂O

نكميلا يتلا ةغيصلا بولطملا اهطيسبت اهطيسبت نكميلا ةيناثلا ةباجلاا ةحيحصلا ةباجلاا يه

• Which of the following is molecular formula

A. CO₂ B. H₂SO₄ C. S₈

D. CH₄O

نكمي يتلا ةغيصلا بولطملا اهطيسبت يتلا هديحولا يه ةثلاثلا ةباجلاا ةباجلاا يه اهطيسبت نكمي ةحيحصلا

O H

H H

H

C C

Cl Cl

Cl

H

CH₄O

CH₃OH

CHCl₃

or

Molecular formula

of Methanol Molecular formula

of Chloroform Write the Molecular formula of Methanol and Chloroform, using the structural formulas below:

Write the empirical formulas for the following molecules if possible:

Compounds Name Molecular Formula Empirical Formula

acetylene C₂H₂ CH

glucose C₆H₁₂O₆ CH₂O

nitrous oxide N₂O N₂O

caffeine C₈H₁₀N₄O₂ C₄H₅N₂O

Ionic compounds

• consist of a combination of cations and an anions

• the sum of the charges on the cation(s) and anion(s) in each formula unit must equal zero

Formula of Ionic Compounds

• Write the formula of magnesium nitride?

• Write the formula of a)chromium sulfate , b)titanium oxide?

Mg ₃N₂

3 × +2 = +6 2 × -3 = -6

Mg ²⁺ N^3-

Cr ₂(SO₄)₃

2 × +3 = +6 3 × -2 = -6

Cr ³⁺ SO₄^2-

Ti ₂O ₄

2 × +4 = +8 4 × -2 = -8

Ti ⁴⁺ O^2-

1. An anion is defined as 

A. a charged atom or group of atoms with a net negative charge.

B. a stable atom.

C. a group of stable atoms.

D. an atom or group of atoms with a net positive charge.

 

2. Atoms of the same element with different mass numbers are called 

A. ions.

B. neutrons.

C. allotropes.

D. chemical families.

E. isotopes.

 

3. How many neutrons are there in an atom of lead ₈₂Pb whose mass number is 208? 

A. 82

B. 126

C. 208

D. 290

E. none of them

4. An atom of the isotope sulfur-31 consists of how many protons, neutrons, and electrons?

(p = proton, n = neutron, e = electron)  A. 15 p, 16 n, 15 e

B. 16 p, 15 n, 16 e C. 16 p, 31 n, 16 e D. 32 p, 31 n, 32 e E. 16 p, 16 n, 15 e  

5. A magnesium ion, Mg²⁺, has 

A. 12 protons and 13 electrons.

B. 24 protons and 26 electrons.

C. 12 protons and 10 electrons.

D. 24 protons and 22 electrons.

E. 12 protons and 14 electrons.

 

6. A sulfide ion, S^2- , has: 

A. 16 protons and 16 electrons B. 32 protons and 16 electrons C. 16 protons and 14 electrons D. 16 protons and 18 electrons E. 32 protons and 18 electrons  

2.7 NAMING COMPOUNDS.

Page 64

) +)

1 2+))

Naming Ionic compounds

Metals

Positive ion Cation

Non metals Negative ion Anion

( 1A , 2A ,3A & transition metals)

Fixed charge metals

Variable charge metals Cations have

same name as the metal element

Ag⁺ silver ion ,Zn²⁺ zinc ion , Al³⁺ Aluminum ion , Li⁺ lithium ion , Ca²⁺ calcium ion

If the metal can form more than 1 cation, the charge is indicated by a Roman numeral in parenthesis after the metal name.

Fe²⁺ iron(II) ,Au⁺ gold(I), Cu⁺ copper(I) , Fe³⁺ iron(III) Au3⁺ gold(III) Cu²⁺ copper (II) Hg₂ ⁺²mercury(I) Hg²⁺ mercury (II)

monoatomic anions

Polyatomic anions

Dr. LAILA AL-HARBI

(STOCK SYSTEM)

Naming Ionic compounds

• 2. Variable charge metals:

• If the metal has more than one oxidation state, the charge is indicated by a Roman numeral in parenthesis after the metal name.

• Most of the transition metals are variable charge metals.

• E.g. Common metals which exist in more than one positive state:

• Fe²⁺ iron(II) ,Au⁺ gold(I), Cu⁺ copper(I) , Fe³⁺ iron(III) Au3⁺ gold(III) Cu²⁺ copper (II) Hg₂ ⁺²mercury(I) Hg²⁺ mercury (II)

• 3. Polyatomic cations: consist of nonmetals:

H₃O⁺ hydronium ion NH₄⁺ ammonium

Dr. LAILA AL-HARBI

Dr. LAILA AL-HARBI

Variable charge metals

Metal (cation)

Divalent elements Monovalent

elements

Lithium (Li⁺) Sodium (Na⁺) Potassium (K⁺) Robidium (Rb⁺) Silver (Ag⁺)

Magnisium (Mg²⁺) Calcium (Ca²⁺) Strontium (Sr²⁺) Barium (Ba²⁺) Lead (Pb²⁺) Zinc (Zn²⁺)

trivalent elements

Aluminium (Al³⁺) Galium (Ga³⁺)

Transition metals

(Fe²⁺) iron(II) (Fe³⁺) iron(III)

(Cr³⁺) chromium (III) (Cu²⁺) cupper (II) (Cu⁺) cupper (I)

(Mn²⁺) manganese(II) (Mn³⁺) manganese(III) (Mn⁴⁺) manganese(IV) (Mn⁷⁺) manganese(VII) (Sn²⁺) stannous or tin(II) (Hg₂²⁺) mercury(I)

(Hg²⁺) mercury(II)

Common name of metal cation:

NH₄⁺ ammonium

• Some Cations of variable charge have name for each oxidation state

• Example

Fe²⁺ iron(II) ferrous , Fe³⁺ iron(III) ferric Cu⁺ copper(I) cuprous , Cu²⁺ Copper (II) cupric Hg₂ ⁺²mercury(I) mercurous

Hg²⁺ mercury (II) mercuric

Mercury (Hg) is the only metal has this formula when it form cation with only one positive charge :

Hg₂²⁺ NOT Hg⁺

The cation of two positive charges has the formula Hg₂⁺

NOTE

Dr.

LAIL A AL- HAR

BI

nonmetal (anion)

Hydrogen hydride (H^-) Oxygen oxide (O^2-) Nitrogen nitride (N ^3-)

Metals form only type of cation

Metals form more than one type of cation (Transition Metals)

1. Group 1A )alkaline Metals(: +1

2. Group 2A )alkaline Earth Metals(: +2 3. Group 3A: +3

4. Group 5A: -3 )= 5-8(

5. Group 6A: -2 )= 6-8(

6. Group 7A )halogens(: -1 )= 7-8(

Nonmetals

• 1. monoatomic anions: change ending to -ide

• E.g. Oxygen→Oxide Sulfur → Sulfide

Hydrogen →Hydride chlorine → Chloride Florine → Floride Bromine → Bromide

• Polyatomic anions: most end in -ate or -ite; usually contain O (oxy)

• Know polyatomic anions on handout.

• Carbonate CO₃^-2 , Nitrate NO₃^{- ,} Sulfate SO₄^-2 ,

• Phosphate PO₄^-3

Cyanide CN^- , Hydroxide OH^- ,Oxide O₂^-2

See table 2.3

B. Naming Anions

Nonmetal polyatomic anions

(SO₄^2-) sulfate , (SO₃^2-) sulfite

(NO₃^-) nitrate (NO₂^-) nitrite

(PO₄^3-) phosphate (PO₃^3- ) phosphite

(ClO₄^– ) perchlorate (ClO₃^- ) chlorate

(HSO₄^-) hydrogen sulfate or bisulfate

(HPO₄^2-) hydrogen phosphate or biphosphate

(CO₃^2–) carbonate

(HCO₃^– ) hydrogen carbonate or bicarbonate (H₂PO₄^-) dihydrogen phosphate

تا تاتيربك تي تيتيربك

• Ionic compounds names start with the positive ion (metal) (include Roman numeral in parenthesis ONLY IF metal has variable charge) followed by the negative ion (nonmetal).

• NaCl Sodium Chloride

• BaCl2 Barium Chloride

• K₂O Potassium oxide

• KNO3 Potassium Nitrate

• Na₂CO₃ Sodium Carbonate

• FeCl2 Iron(II) Chloride → ferrous Chloride

• FeCl3 Iron(III) Chloride → ferric Chloride

• Cr₂S3 Chromium(III) Sulfide

• (NH₄)₃PO₄ Ammonium Phosphate

• Cu(NO₃)₂ Cupper(II)nitrate

• PbO Lead(II) oxide

Example 2.5 p61:

Name the following compounds:

(a) Cu(NO₃)₂

1. Cation: Copper cation (can form two types of cation →Stock system) →

Copper (II)

2. Anion: NO₃^- anion has a common name Nitrate

Thus: the name of the compound is:

Copper (II) nitrate

لُدابت ةٍدعَاق تِاؤفِاكتَلا

Dr. LAILA AL-HARBI

(b) KH

₂

PO

₄

1. Cation: K form only one type of cation

→ Potassium Note: not potassium (I) 2. Anion: H₂PO₄^-has a common name dihydrogen phosphate

Thus: the name of the compound is:

Potasium dihydroen phosphate

Dr. LAILA AL-HARBI

• Write the chemical formula for the following

compounds

• Mercury(I)nitrite Hg₂ (NO₂)₂

• Cesium sulfide Ce₂S

Calcium phosphate

 Ca₃ (PO₄)₂

• Write the chemical formula for the following

compounds

• Rubidium sulfate

• Rb ₂ SO₄

• Barium hydride

• BaH ₂

Name the following ionic compounds:

Cu(NO₃)₂ KH₂PO₄ NH₄SCN

H₂O₂ Li₂SO₃ Ca₃(PO₃)₂ KMnO₄

Cupper(II) nitrate

Potassium dihydrogen phosphate Ammonium thiocyanate

Hydrogen peroxide Lithium sulfite Calcium phosphite

Potassium permenganate Hg₂Cl₂ Mercury(I) chloride

K₂CrO₄ Potassium chromate Br₂O₇ Dibromine heptoxide

Write formulas for the following ionic compounds:

MnO K₂HPO₄ NH₄ClO₂

Pb(OH)₂ NaHCO₃ Ba(CN)₂ RbHSO₄ HgBr₂ Manganese(II) oxide

Potassium hydrogen phosphate Ammonium chlorite

Lead hydroxide Sodium bicarbonate Barium cyanide

Rubidium hydrogensulfate Mercury(II) bromide

SrH₂ Strontium hydride

• Ionic Compounds

• often a metal (cation) + nonmetal (anion)

• The cation is always named first and the anion second

• anion (nonmetal), add “ide” to element name

ةينويَلأَا تِابكِرُمَلا نم مسلإا نوكتي •

زلفلالا هيلي زلفلا فاضي • ide

زلفلالل

Mg(OH)₂ magnesium hydroxide

KCN potassium cyanide

2.7

BaCl₂ barium chloride K₂O potassium oxide

1. Binary compounds are compounds formed from just two elements

2. Ternary compounds are compounds formed from three elements.

Ionic compounds

Molecular Compounds

Diborane B₂H₆

Methane CH₄

Silane SiH₄

Ammonia NH₃

Phosphine PH₃

Water H₂O

Hydrogen sulfide H₂S

2- common names of some molecular compounds

ةيئيَزُجلا تِابكِرُمَلا 

لا + تازلف هابشأ نم نوكتت •

تازلف تازلف لا + تازلف لا •

ةيئيزجلا تابكرملا مظعم •

نوكتت) رصنعلا ةيئانث نوكت (طقف نيرصنع نم لثم هعئاش ءامسأ هل اهضعب •

H₂O, NH₃, CH₄ 

هتياهنل فاضي ريخلأا رصنعلا •

ide

1- Consists of (metalloid + nonmetal)

or (nonmetal + nonmetal)

Many molecular compounds are binary compounds

PCl3

SiC

3- last element ends in -ide

4- element further left in periodic table is 1^st (less electronegative)

(HCl) H(1A) and Cl(7A), so hydrogen is 1^st, the name is

hydrogen chloride

5- element closest to bottom of group is 1^st (less electronegative)

(SiC) Si(4A) and C also belongs to

(4A) ,but (Si) is closest to bottom of the group, so silicon is 1^st ,

the name is silicon carbide

رصانعلا بتكت •

لودجلا راسي هدوجوملا برقلأا وأ يرودلا .لاوأ راسيلل ةيوتحملا تابكرملا •

نم ةرذ نم رثكأ ىلع نع ربعي رصنعلا سفن رصنعلل تارذلا ددع تائدابلا مادختساب اهل ةينانويلا

6- if more than one compound can be formed from the same elements, use prefixes to indicate number of each kind of atom.

Examples

Note

• Note that mono- is never used for the first element

• For oxides, the ending “a” in the prefix is omitted.

• N₂O₄ dinitrogen tetroxide not (dinitrogen tetraoxide)

• For oxides, the ending “o” in the prefix is omitted.

• N₂O dinitrogen monoxide not (dinitrogen monooxide )

Dr. LAILA AL-HARBI

HI hydrogen iodide

PF₃ phosphorus trifluoride H₂O₂ Hydrogen peroxide

N₂O₄ dinitrogen tetraoxide

NO₂ nitrogen dioxide

N₂O dinitrogen monooxide

Examples of Molecular Compounds

2.7 TOXIC!

Laughing Gas

ICl₃ Iodine trichloride

Name the following molecular compounds:

SO₂ SiCl₄ BrF₇ P₄O₁₀ Cl₂O₇ CH₄ CS₂

Sulpher dioxide

Silicon tetrachloride Bromine heptaflouride

Tetraphosphorus decoxide Dichlorine heptoxide

Methane

Carbon disulphide Br₂O₇ Dibromine heptoxide

Write formulas for the following molecular compounds:

SF₄ N₂O₅ SO₃ Si₂Br₆ PCl₅ P₄S₁₀ N₂O₂ Sulphur tetraflouride

Dinitrogen pentoxide Sulfur trioxide

Disilicon hexabromide

Phosphorus pentachloride

Tetraphosphorus decasulphide Nitrogen peroxide

CO Carbon monoxide

IF₇ Iodine heptaflouride

Fill the blanks in the following table

name formula anion cation

Barium bicarbonate Ba(HCO₃)₂ ^-HCO₃ ⁺Ba² Iron(III)nitrite Fe(NO₂)₃ ^-NO₂ ⁺Fe³

Hyrdogen flouride HF ^-F ⁺H

Manganise(IV)oxide MnO₂ ^-O^{2 +}Mn⁴

Sodium peroxide Na₂O₂ ^-O₂^{2 +}Na

Cesium chlorate CsClO₃ ^-ClO₃ ⁺Cs

Lithium nitride Li₃N ^-N^{3 +}Li

• Which of these pairs of elements would be most likely to form an ionic compound? 

(a) P and Br (b) Cu and K (c) C and O (d) O and Zn (e) Al and Rb

• Which of these pairs of elements would be most likely to form a molecular compound?

(a) Na and Br (b) C and O (c) Ca and O (d) Zn and O (e) Mg and Cl

8. Which of the following compounds is named lithium carbonate?

  A) Na₂CO₃   B) LiHCO₃

  C) LiCO

  D) Li₂CO₃

9. What is the name of KClO?

  A) potassium chlorite   B) potassium chloride   C) potassium hypochlorite   D) potassium oxide

10. What is the formula for ammonium sulfate?

  A) NH₄SO₄   B) NH₄(SO₄)₂   C) (NH₄)₂SO₄   D) NH₄S