PhySci Practice: Naming Compounds

Naming Compounds

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Naming Ionic Compounds

Main Group Elements

The name of ionic compounds in the main group of elements is made of the names of the ions it is made of.

There are no prefixes that tell you what subscripts are in the formula.

Anions always end in "ide"

Ionic Compound Naming

​Notice that the name of each compound just has the name of the cation and anion. There are no prefixes or other information to tell you the subscripts to use.

Calcium Fluoride

​​Sodium Bromide

Aluminum Sulfide

Writing Ionic Formulas

Main Group Elements

The name does not tell you what subscripts are needed.

To determine the subscripts, you must find the charge of each ion and determine how many cations and anions are needed to make the overall charge = 0.

Ionic Compound Naming

Multiple Choice

What is the correct chemical formula for magnesium iodide?

• MgI₂

• Mg₂I

• MgI

• Mg₂I₂

Multiple Choice

What is the correct name of the compound CaCl₂?

• Calcium dichloride

• Calcium dichlorine

• Calcium chlorine

• Calcium chloride

Multiple Choice

What is the correct name for the compound LiF?

• Lithium fluoride

• Lithium fluorine

• monolithium monofluoride

• lithium monofluoride

Multiple Choice

Name the ionic compound, LiCl

• lithium chlorine

• lithium chloride

• lithium chlorate

• lithium monochloride

Multiple Choice

What is the formula for calcium phosphide?

• CaP

• Ca₂P₃

• Ca₃P₂

• Ca₂P

Multiple Choice

The chemical formula for an ionic compound of potassium and oxygen is

• KO.

• K₂O.

• K₂O₂.

• KO₂.

Naming Covalent Compounds

Covalent Compounds (or Molecular Compounds)

Covalent compounds can join in multiple ways. Therefore, the name of a covalent compound must include prefixes that describe how many atoms of each element are needed to make the compound. Recognizing these prefixes will allow you to write the name based on the formula or the formula based on the name.

Ionic Compound Naming

Covalent Exceptions

​Exceptions to Covalent Naming Rules

1) You do not have to put "mono" if there is only 1 of the first element in the compound.

2) The 3 most common covalent compounds can be called by their common name. You must remember their formula.

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phosphorus pentafluoride

​PF₅

Examples of Covalent Exceptions

Names and Formulas of Covalent Compounds

N₂O₅

• Notice the first compound has no prefix for phosphorus. That's because there is only 1 phosphorus atom AND it is first.

• The 2nd compound has prefixes on both- any element with more than 1 atom MUST have a prefix if it is covalent.

• The 3rd compound has "mono" on the 2nd element but nothing on the 1st. This is because "mono" can only be left off the 1st element. If there is only 1 of the 2nd element, mono must be used.

dinitrogen pentaoxide

ICl

iodine monochloride

Multiple Choice

Name the compound: N₂O₅.

• dinitrogen pentaoxide

• binitrogen pentaoxide

• nitrogen oxide

• pentanitrogen dioxide

Multiple Choice

Name the compound: SO₃

• sulfur trioxide

• sulfite ion

• sulfur oxide

• sodium trioxide

Multiple Choice

Name the compound: P₄O₈

• tetraphosphorus octoxide

• phosphorus oxide

• tetrapotassium octoxide

• potassium oxide

Multiple Choice

Write the formula: iodine heptafluoride

• IF₇

• I_2F₁₄

• IHF₇

• IF₆

Multiple Choice

Write the formula: nitrogen trichloride

• NCl₃

• N₁Cl₃

• N₁Cl₅

• Cl₃N

H₂O

3 common covalent compounds to remember

Examples of Covalent Exceptions

Names and Formulas of Covalent Compounds

CH₄

NH₃

Water

Methane

Ammonia

When you have both covalent and ionic compounds mixed, you must determine whether it is ionic or covalent before writing the name or formula.

• Ionic names: no prefixes

• Ionic formula: add ions until charge = 0

• Covalent names: use prefixes

• Covalent formulas: use prefixes

​

​Ionic = metal + nonmetal; Covalent = nonmetal + nonmetal

​Mixed Names and Formulas

Multiple Select

H₂0 - name?

• hydrooxic acid

• hydrogen oxygen

• water

• hydrogen oxide

Multiple Choice

silicon dioxide

• SO₂

• NaO₂

• SiO₂

• SiO

Multiple Choice

SiCl₄

• silicon tetrachloride

• silicon quadchloride

• monosilicon tetrachloride

• silicon chloride

Multiple Choice

The name of P₄S₁₀ is

• phosphorous sulfide

• phosphorus sulfide

• tetraphosphorus decasulfide

• phosphorus (X) sulfide

Multiple Choice

What is the correct formula for the compound, lithium oxide?

• LiO

• Li₂O

• LiO₂

• Li₂O₂

Multiple Choice

Name the compound AlBr₃

• aluminum bromide

• aluminum tribromide

• aluminum bromine

• aluminum boride

Multiple Choice

What is the name of N₂O₃

• Nitrogen trioxide

• Dinitrogen oxide

• Dinitrogen trioxide

• Nitrogen oxide

Multiple Choice

In a(n) ________ electrons are transferred from one atom to another

• ionic compound

• covalent compound

Multiple Choice

Name the following ionic compound: Cs₂S

• cesium sulfide

• cesium sulfate

• cesium II sulfate

• cesium II sulfide

Multiple Choice

Which of the following is the correct formula for carbon monoxide?

• $$CO$$  

• $$C_1O_1$$  

• $$CO_2$$  

• $$C_2O$$  

Multiple Choice

Formula for barium sulfide

• B₂S₃

• BaS

• Ba₂S

• BaS₂

Multiple Choice

Name for NaH

• sodium hydrogen

• potassium hydride

• sodium hydride

• potassium hydrogen

Multiple Choice

Name this compound.
MgF₂

• magnesium fluoride

• manganese Phosphide

• magnesium(III) fluoride

• magnesium fluoride(II)