PhySci Final Review 7: Compounds

PhySci Final Review 7: Compounds

By William Lovering

Ions are elements with a positive (+) or negative (-) charge.

Valence Electrons and Ions

• Atoms gain or lose electrons from the highest energy level.

• The atoms in the highest energy level are called valence electrons.

• To find the number of valence electrons in an atom of a representative element, simply look at its representative group number.

• Elements in group 15 like nitrogen have 5 valence electrons.

Atoms want to have a "full" outer shell (orbital) of 8 electrons.

Hydrogen (H) and Helium (He) are the only exceptions- They have 2 in the first shell (orbital).

Octet Rule

• The octet rule determines if an atom will gain or lose electrons.

• The outer level of an atom has eight electrons.

• An atom will gain or lose electrons to have a full outer energy level.

• Atoms of metals tend to lose their valence electrons. Nonmetals tend to gain or share electrons to achieve a full octet.

Will an atom gain or lose an electron?

• Atoms in group 1, 2, and 13 lose electrons. Remember the atom want a full outer energy level.

• For atoms that lose electrons, they empty the outer most energy level.

• For groups 1 - 13: atoms lose electrons forming a positive ion.

• For groups 15 - 17: atoms gain electrons forming a negative ion.

• For group 14: atoms can gain or lose electrons forming a positive or negative ion.

Chemical Formulas

• In chemical reactions, the atoms in molecules separate and recombine to form new compounds.

• To tell which and how many elements are in compounds, we use chemical formulas.

• Chemical formulas are a mix of element symbols and subscripts.

Chemical Formulas

• When you look at a chemical formula, it is very similar to an XYZ formula in Math class.

• Na₂SO₄

• Na₂ = 2 Sodium Atoms

• S = 1 Sulfur Atom (when there is no subscript, it is understood to be 1).

• O₄ = 4 Oxygen Atoms

Electrons are the Key

• If valence electrons are shared by atoms, it is called COVALENT bonding

• If valence electrons move freely between atoms, it is called METALLIC bonding

• If valence electrons are transferred from one atom to another, it is called IONIC Bonding

Ionic Bonds

• Form Crystalline Lattice (crystals)

• Have high melting and boiling points

• Hard

• Brittle

• Conduct electricity when dissolved in water

What you need to remember...

• Metals + Nonmetals

• Make IONIC bonds

• Transfer electrons

• High electronegativity difference

Covalent Compounds

• Have Lower melting and boiling points

• Tend to be flammable

• When dissolved in water they do not conduct electricity

• Soft or brittle solid

• Can also form crystals

What you need to remember

• Nonmetal + Nonmetal

• Make COVALENT bonds

• Share electrons

• Low electronegativity difference

Metallic Bonds

• good conductors of heat and electricity

• malleable and ductile

• lustrous

• opaque

What you need to remember

• Metal ions near each other share valence electrons

• These valence electrons flow freely between all of the ions

• These delocalized electrons are why metals conduct heat and electricity

• It is also why metals are malleable and ductile

​Properties of ionic and covalent molecular substances

When naming or writing compounds, the first step is to determine if the compound is ionic or covalent.

What is the difference?

Naming Ionic Compounds

Rules for Naming Cations

• When metals lose electrons they become ions, but their name does not change.

Rules for Naming Anions

• When nonmetals gain electrons they become ions, and their name does change.

Rules of Naming Ions

• The names of metals do not change.

• Changing the name of nonmetals:

• root of element name + -ide  = name of anion

• Examples:

  The name of chlorine’s ion: chlor-  +  -ide  =  chloride

• The name of calcium’s ion: calcium

  (The names of metals don’t change!)

• The name of nitrogen’s ion: nitr-  +  -ide  =  nitride

Steps for Naming Ionic Compounds

Step 1: Write the name of the metal ion.

Step 2: Write the name of the nonmetal ion.



Step 3: YOU ARE DONE! It is that easy.

Example: CaBr₂

_{Calcium Bromide}

Writing Ionic Compound Formulas

physical science

naming covalent compounds

Multiple Choice

Na ionizes to a charge of _______

• +1

• +2

• -1

• -2

Multiple Choice

K ionizes to a charge of _________.

• +1

• +2

• -1

• -2

Multiple Choice

Mg ionizes to a charge of ______.

• +1

• +2

• -1

• -2

Multiple Choice

Al ionizes to a charge of _______.

• +3

• -3

• +2

• -2

Multiple Choice

P ionizes to a charge of _______.

• +3

• -3

• +2

• -2

Multiple Choice

O ionizes to a charge of ________.

• +1

• +2

• -1

• -2

Multiple Choice

S ionizes to a charge of _______.

• -2

• -1

• +1

• +2

Multiple Choice

An atom becomes _________ when it gains electrons.

• Positive
• Negative
• Neutral
• Invinsible

Multiple Choice

An atom becomes _______ when it loses electrons.

• Positive
• Negative
• Neutral
• Invinsible

Multiple Choice

Cations are...

• Positive
• Negative
• Neutral
• Purring

Multiple Choice

Anions are...

• Positive
• Negative
• Neutral
• Crying

Multiple Choice

What is the name of this ion?

• oxide

• oxygen

Multiple Choice

Why are ions formed?

• To make our lives difficult

• Because atoms want to be stable with 8 valence electrons

• Because atoms have the same number of protons and electrons

• Because atoms gained neutrons

Multiple Choice

An atom with 2 protons, 3 neutrons, and 4 electrons has a charge of ____.

• +2

• -2

• +3

• 0

Multiple Choice

Elements on the LEFT side of the periodic table will most likely form:

• Positive ions
• Negative ions
• Neutral Ions
• None of these

Multiple Choice

A bond between a metal and a nonmetal is called a(n)

• covalent bond

• ionic bond

• metallic bond

• transfer bond

Multiple Choice

What type of bond involves the sharing of electrons between atoms?

• covalent bond

• ionic bond

• metallic bond

• transfer bond

Multiple Choice

Identify the following compound as ionic or covalent: MgO

• ionic

• covalent

Multiple Choice

Identify the following compound as ionic or covalent: Na₂SO₄

• ionic

• covalent

Multiple Choice

Identify the following compound as ionic or covalent: SO₂

• ionic

• covalent

Multiple Choice

When naming covalent compounds...

• You need roman numerals and no prefixes

• You do not need roman numerals or prefixes

• You need roman numerals and prefixes

• You do not need roman numerals but you do need prefixes

Multiple Choice

What type of bond occurs between a positive and a negative ion?

• Ionic bond
• covalent bond
• metallic bond
• p-n bond

Multiple Choice

A substance which has a high melting point, conducts electricity when dissolved in water, and has a crystalline structure probably has what type of bond?

• Ionic
• Metallic
• Covalent
• Crystalline

Multiple Choice

What type of bond is present when electrons are freely shared between metal atoms?

• Metallic
• Ionic
• Covalent
• Hippie

Multiple Choice

Which formula represents an covalent compound?

• CO₂
• Ag
• FeCl₃
• Cs₃P

Multiple Choice

Which of the following is NOT a property of ionic compounds?

• They have very high melting points
• They conduct electricity when in solution
• They have high boiling points
• They are insoluble in water

Multiple Choice

Where are the nonmetals located on the periodic table? 

• Blue
• Red
• Green

Multiple Choice

What is the correct formula for this molecule?

• NH
• N₃H
• NH₃
• NH₄

Multiple Choice

Some are solids, some are liquids, and some are gases at room temperature.

• ionic compounds
• covalent compounds

Multiple Choice

Molten compound does NOT conduct electricity.

• ionic compound
• covalent compound

Multiple Choice

Have a high m.p. (1000°C-3000°C)

• ionic compounds
• covalent compounds

Multiple Choice

usually hard but brittle

• ionic compounds
• covalent compounds

Multiple Choice

Name the following compound; ScCl₂

• sulfur dichloride
• scandium chloride
• scandium (II) chloride
• scandium dichloride

Multiple Choice

Which of the following is the metallic ion in copper (II) chloride?

• Cu²⁺
• Cu^2-
• Co^2-
• Cl²⁺

Multiple Choice

The correct name for P₂O₅ is

• potassium oxide

• dipotassium pentoxide

• diphosphorus pentoxide

• phosphorus oxide

Multiple Choice

The correct name for CaBr₂ is

• calcium dibromide

• calcium (II) bromide

• calcium bromide

• carbon bromide

Multiple Choice

The formula for sulfur hexafluoride is

• S₆F

• SF₆

• SuF₅

• SFl₆

Multiple Choice

What is the name of the compound Mg₃N₂?

• manganese (II) nitride

• magnesium nitride

• magnesium nitrogen

• magnesium (II) nitride

Multiple Choice

What is the correct name for NO?

• Mononitrogen Monoxide
• Nitrogen Monoxide
• Mononitrogen Dioxide
• Nitrogen Oxide

Multiple Choice

Phosphorous trichloride

• PCl₃
  
• P₃Cl
• P₃Cl₃
• PCL

Multiple Choice

The covalent compound N₂O₅ would be named

• nitrogen oxide.
• dinitrogen oxide.
• nitrogen pentoxide.
• dinitrogen pentoxide.

Multiple Choice

What region of the periodic table contains atoms that form covalent bonds?

• the left side
• the middle
• the right side
• top left

Multiple Choice

Phosphorous trichloride (covalent)

• PCl₃

• P₃Cl

• P₃Cl₃

• PCL

Multiple Choice

What is the NAME of this ionic compound....

Na₂S

• sodide (II) sulfide

• sodium sulfide

• disodium sulfide

• sodium sulfur

Multiple Choice

What is the NAME of this ionic compound....

Mg₃N₂

• magnesium (III) nitrogen

• magnide nitride

• magnesium (II) nitrogen

• magnesium nitride