Chem Labcon (Naming)

8/6/2019 Chem Labcon (Naming)

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1. Naming TWO NON-METALS

Binary Compounds of Two Nonmetals

Given Formula, Write the Name

The Greek System

A binary compound is one made of two different elements. There can be one of each element

such as in CO or NO. There can also be several of each element such as BF or

OCl2.


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Attach the selected prefix to the name of the first element in the formula. If no prefix is to

be used, begin with the name of the first element.

Example: We indicate the N2 portion of N2O3 withdinitrogen.

Select a prefix to identify the subscript for the second element (even if its subscript is

understood to be one).Leave the "a" off the end of the prefixes that end in "a" and the o off of

mono- if they are placed in front of an element whose name begins with a vowel (oxygen oriodine).

Example: The name of N2O3 grows to dinitrogen tri-.

Write the root of the name of the second element in the formula as shown below.

Example: The name of N2O3 becomes dinitrogen triox-.

Add -ide to the end of the name.

Example: The name of N2O3 is dinitrogen trioxide.

Prefixes

1 - mon(o)

2 - di

3 - tri

4 - tetr(a)5 - pent(a)

6 - hex(a)7 - hept(a)

8 - oct(a)

9 - non(a)

10 - dec(a)

Roots of the Nonmetals

H - hyd

C - carb

N - nitr

P - phosphAs - arsen

O - oxS - sulf

Se - selen

F - fluor

Cl - chlorBr - brom

I - iod

Exceptions

Hydrogen atoms always form one covalent bond, and halogen atoms (group 17 or 7A) usually

form one bond. Thus hydrogen reacts with halogens to form compounds with the general

formula of HX, with the X representing the halogen. Because this is common knowledge amongscientists and science students, these compounds are often named without prefixes. For example,

HF can be named hydrogen fluoride or hydrogen monofluoride. Likewise, HCl can be named

hydrogen chloride or hydrogen monochloride, HBr can be named hydrogen bromide or hydrogenmonobromide, and HI can be named hydrogen iodide or hydrogen moniodide. For similar

reasons, H2S can be named hydrogen sulfide or dihydrogen monosulfide.

Converting Names to Formulas

The first step in writing formulas when given the systematic name of a binary covalent

compound is to recognize the name as representing a binary covalent compound. It will have one

of the following general forms.

prefix (name of nonmetal) prefix (root of name of nonmetal)ide (e.g. dinitrogen pentoxide)

or(name of nonmetal) prefix (root of name of nonmetal) ide(e.g. carbon dioxide)

or(name of nonmetal) (root of nonmetal) ide (e.g. hydrogen fluoride)Follow these steps for writing formulas for binary covalent compounds when you are given a

systematic name. Notice that they are the reverse of the steps for writing names from chemical

formulas.

Write the symbols for the elements in the order mentioned in the name.


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Write subscripts indicated by the prefixes. If the first part of the name has no prefix,

assume it is mono-.

Remember that HF, HCl, HBr, HI, and H2S are often named without prefixes. You will also beexpected to write formulas for the compounds whose nonsystematic names are listed above.

3. Naming HYDROXIDE AND A METAL

Naming Ionic Compounds

Key Concepts

Positively charged ions are called cations

Negatively charged ions are called anions

The cation is always named first.

Cations

Cations can be metals or polyatomic ions

The ammonium ion (NH4+) is an example of a polyatomic cation Hydrogen can also form a cation, H+, in which case the name hydrogen is used in naming.

For metals that have only one possible charge (valency) the name of the metal is used.Examples are Group I metals (charge 1+), Group II metals (charge 2+), Aluminium (charge 3+), Zinc

(charge 2+), Silver (charge 1+)

For metals that can have more than one charge (valency) the name of the metal is succeeded by

the valency in capital Roman numerals in brackets

OR

by using the suffix -ous for the lowest valency and -ic for the highest valency and sometimes with the

Latinised name for the metal

Anions

Anions can be a negatively charged element or a polyatomic ion

Negatively charged elements have the suffix -ide

Examples are oxide (O2-), sulfide (S2-), fluoride (F-), chloride (Cl-), bromide (Br-), iodide (I-), nitride

(N3-), hydride (H-)

Polyatomic ions which include oxygen in the anion have the suffixes -ate or -ite. "ate" means

there is more oxygen in the anion than one ending in "ite"

Element Cation Preferred Name Other Name

copperCu+ copper (I) cuprous

Cu2+ copper (II) cupric

iron Fe2+

iron (II) ferrousFe3+ iron (III) ferric

leadPb2+ lead (II) plumbous

Pb4+ lead (IV) plumbic

mercuryHg2

2+ mercury (I) mercurous

Hg2+ mercury (II) mercuric

tinSn2+ tin (II) stannous

Sn4+ tin (IV) stannic


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Examples: sulfate (SO42-) has more oxygen than sulfite (SO32-), nitrate (NO3-) has more oxygen in the

anion than nitrite (NO2-)

Other examples are carbonate (CO32-), phosphate (PO43-) and permanganate (MnO4-)

Exception: OH- is named hydroxide

ExamplesIonic Compounds containing ions of elements

MgOCATION: Mg2+ is named magnesium as magnesium belongs to Group (II) and can only have one charge

(valency)

ANION: O2- is named oxide

Name of compound is magnesium oxide

FeS

CATION: Fe2+ is named iron (II) or ferrous as iron can have a charge of either 2+ or 3+

ANION: S2- is named as sulfide

Name of compound is iron (II) sulfide or ferrous sulfide

LiH

CATION: Li+ is named as lithium since lithium is a Group I metal and can have only one charge

(valency)

ANION: H- is named as hydrideName of compund is lithium hydride

H2S

CATION: H+ is named as hydrogen

ANION: S2- is named as sulfideName of compound is hydrogen sulfide

Ionic compounds containing polyatomic ions

NaOH

CATION: Na+ is named as sodium (Group I metal)

ANION: OH- is named as hydroxide

Name of compound is sodium hydroxide

CaCO3

CATION: Ca2+ is named as calcium (Group II metal)ANION: CO32- is named as carbonate

Name of compound is calcium carbonate

FeSO4

CATION: Fe2+ named as iron (II) or ferrous

ANION: SO42- named as sulfate

Name of compound is iron (II) sulfate or ferrous sulfate

FeSO3

CATION: Fe2+ named as iron (II) or ferrous

ANION: SO32- named as sulfite

Name of compound is iron (II) sulfite or ferrous sulfite (NH4)3PO4

CATION: NH4+ named as ammoniumANION: PO43- named as phosphate

Name of compound is ammonium phosphate

Chem Labcon (Naming)

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