Chemistry- Ch6

How are ionic compounds formed?

When valence electrons of a metal atom are transferred to the atom of a nonmetal.

Why do the noble gases not react very easily to form compounds?

They have a filled outer level. (stable)

What is the octet rule?

This says that every atom bonds to achieve a full outer level of electrons. For most atoms that is 8 outer electrons. 

What are ionic bonds?

Ions form when atoms gain or lose their valence electrons to form a stable electron configuration. 

What are covalent bonds?

Bonds between non-metals where e- are shared. 

What is a ion?

A charged atom W

What is ionic charge?

+or -

What are cations?

Positive ions

What are anions?

Negative ions

How does the size of an atom compare to the size of its ion?

metals- atoms (larger), cations (smaller)

non-metals- atoms (smaller), anions (larger)

What are some properties of ionic compounds?

1. exist as crystalline solids

2. high melting points

3. conduct electricity when melted or dissolved in water

What is binary compounds? Examples.

Compound composed of 2 kinds of element.

Ex. NaCl, K2S, MgO

What are the rules for writing formulas for binary ionic compounds?

1. write the symbol of the first element with its charge. Write the symbol of the second element with its charge.

2. Criss-cross the absolute value of the charges and place them as subscripts.

3. If charges already add up to zero- there is no need to criss cross.

What are the rules for naming binary compounds?

1. write the name of the first element in the compound unchanged

2. write the name of the second element in the compound with the -ide ending 

3. I- iodine Br- bromide O- oxide S- sulfide Cl- chloride F-fluoride N- nitride P- phosphide H- hydride 

4. use lower case when writing the name

What do we mean when we say an element has multiple valences?

Elements have ions with more than one charge.

How do we name compounds when elements have multiple valence?

1. Write the name of the first element in the compound followed by a roman numeral which represents the charge of the ion.

2. Write the name of the second element with an “ide” ending

What is a ternary compound?

A compound composed of three kinds of elements. They contain a polyatomic ion. 

What is a polyatomic ion?

A group of atoms with a single charge. Stable grouping.

Rules for writing formulas for ternary compounds

1. Write the symbol of the first element or polyatomic ion with its charge

2. Write the symbol of the second element or polyatomic ion with its charge

3. Criss-cross the charges and place as subscripts. Use parenthesis where necessary

Rules for naming ternary compounds 

1. Name the first element or polyatomic ion unchanged 

2. Name the second if an element with an “ide” ending. Name the second if a polyatomic ion unchanged

3. Ue roman numerals if necessary 

What is a chemical bond?

Simultaeous attraction of electrons to two nuclei.

How does potential energy change when a chemical bond is formed?

P.E. is lowered- more stable

How does potential energy change when a chemical bond is broken?

PE. increases

Compare the potential energy of two atoms when bonded to their condition when separated.

P.E. is low bonded - P.E. higher unbonded

Describe two ways in which the valence electrons of atoms participate in bond formation

1. e- can be shared

2. e- can be transferred

What is an ionic bond?

Bond between a metal or nonmetal

Ionic bonding basically occurs between blank and blank elements

Blank: metals

2nd blank: non-metallic

What role do valence electrons play in covalent bonding?

Valence electrons are shared