Covalent (Molecular) Naming & Formulas
The ending of the first element's name in a covalent compound does not change. What happens to the second element in the compound?
The ending of the second element in the compound is changed to "-ide."
How is an ionic bond formed?
Two ions (one positive and one negative) form an ionic bond by transferring electrons.
Name 2 facts about acids.
An acid is a substance that dissociates in water to produce one or more hydrogen ions, H+
Sour
Conducts electricity
When reacting with phenolphthalein, stays clear
What does the following describe?: Involves having a larger compound break down into smaller parts. One substance is on the reactant side.
General Equation: XY → X + Y
Decomposition
What is a BR (Brother Rutherford) diagram?
A BR diagram is a simple atomic model that shows the number of electrons in each shell of an atom
T or F: Hydrogen always acts as a metal.
Answer: False
Correction: IF it is found first in the compound, it is considered a metal. Use ionic naming rules and its form does not change in the name. Ex: HF is hydrogen fluoride.
IF it is written second in the compound, it is acting as a non-metal and its ending changes to “-ide”, becoming hydride. Use covalent (molecular) naming. Whether you use prefixes or not depends on the first element! Ex: PH3 is phosphorous trihydride.
A binary compound is made up of only 2 elements, a metal and a non-metal. How is a binary compound named?
Step 1: Write the name of the METAL
Step 2: Write the name of the NON-METAL
Change the ended of the NON-METAL to “ide”
Name 2 facts about bases.
A base is a substance that dissociates in water to produce one or more hydroxide ions, OH-
Bitter
Conducts electricity
Slippery
When reacting with phenolphthalein, turns pink
Substances 8-14 on the pH scale are basic/alkali
What does the following describe?: Two or more smaller reactants combine to produce a new single bigger product. One substance always ends up on the product side.
The general equation for this type of reaction is:
X + Y → XY
Synthesis
T or F: Generally, the 1st electron shell can only hold 2 electrons, and the 2nd+ can hold up to 8.
True
The names of covalent compounds have prefixes added to their names. Name them from 1-10.
1: mono-
2: di-
3: tri-
4: tetra-
5: penta-
6: hexa-
7: hepta-
8: octa-
9: nona-
10: deca-
How do you name a multivalent compound (contains a metal that exhibits more than one possible valence)?
Step 1: The name of the metal is written first, followed by the charge of the metal using Roman numerals
Step 2: Then, the name of the nonmetal is written and the ending is changed to “ide”.
Ex: CoCl2 is composed of Co2+, cobalt (II) ions, and Cl-, chloride ions, so it is called cobalt (II) chloride.
The acronym HOFBRINCL contains diatomic molecules, molecules that are always paired together in 2 when they are alone. What are the names of the diatomic molecules in the acronym?
Hydrogen, Oxygen, Fluorine, Bromine, Iodine, Nitrogen, and Chlorine
What is the following an example of?:
Fuel + Oxygen → Carbon monoxide + Water + soot
Incomplete Combustion
T or F: In a Lewis Dot diagram, the dots around the atom symbol is equal to the amount of electrons in the atom.
Answer: False
Correction: In a Lewis Dot diagram, the dots around the atom symbol is equal to the number of valence electrons
What does the following describe?:
Formed between two or more non-metals
Covalent bond formed from sharing electrons
Covalent (Molecular) Compounds
In a tertiary compound (a compound that contains a polyatomic ion), do we change the ending of the polyatomic ion?
Answer: No.
Ex: Na2CO3 is sodium carbonate
What are precipitates and when do they occur?
A precipitate is a solid that is created when two aqueous compounds react. This occurs when two elements are bonded, but INSOLUBLE
In a single displacement reaction, an element by itself attempts to displace another element that is in a compound.
The element MUST be more reactive than the element it is trying to displace.
METALS can ONLY displace other METALS
NON-METALS can ONLY displace other NON-METALS
General Formula: A + BX → B + AX
In a Lewis Dot Diagram, the dots are placed around the atom in sequence. Fill in the blanks:
__ than four valence electrons:
Place each one around the atom on their own
___ than four valence electrons:
Go back and double up on the other dots
A) More
B) Less
LESS than four valence electrons:
Place each one around the atom on their own
MORE than four valence electrons:
Go back and double up on the other dots
How do you write the chemical formula for covalent compounds?
From the name determine the elements in the compound. Write out their element symbols.
Using the prefixes in the chemical name, determine how many of each element are present. These become the subscripts for the chemical formula.
Write the chemical formula!
**For COVALENT compounds, we do NOT have to determine the ionic charges - just use the name to determine the formula!
List the steps one must take to create a chemical formula for an ionic compound.
From the name determine the elements in the compound. The metal is listed first; Non-metal(s) second
Using the periodic table, determine the ionic charge on the element. Metals LOSE electrons, therefore will be POSITIVELY charged. Non-metals GAIN electrons, therefore will be NEGATIVELY charged.
Once you determine the ionic charges, criss-cross the charges to create subscripts for the chemical formula. If the non-metal is a POLYATOMIC ION, you may need to use brackets!
What does the Law of Conservation of Mass state?
The Law of Conservation of Mass states that in any chemical reaction, the mass of the products is always equal to the mass of the reactants.
Name 2 facts about double displacement reactions.
In a double displacement reaction, the cations (metals) in two compounds switch places to form two new compounds;
Use SOLUBILITY RULES
General formula: AX + BY → AY + BX
*Metals bond with non-metals; you cannot have two metals together!*
What does the following describe?:
An atom will gain or lose electrons to obtain 8 electrons in it's outer shell. In other words, elements want to reach an electron configuration of the nearest noble gas.
The Octet Rule