Lesson 5- Lesson - Molecular Compounds

Question 1

What are 7 elements that never exist as a single neutral atom
and how do they exist?

Answer 1

, they form covalent bond(s) with themselves and exist as diatomic molecules

H, O, F, Br, I, N, Cl ALWAYS exist as H2, O2, F2, Br2, I2, N2, Cl2

Question 2

Non-bonded pair of electrons, called a…

Answer 2

lone pair

Question 3

1 pair of shared/bonded electrons

Answer 3

1 covalent bond)

Question 4

RULES FOR: Drawing Lewis Structures for more complicated molecular compounds

Answer 4

Rule 1: The central atom is usually the least electronegative atom (or largest bonding capacity)

Rule 2: Other atoms surround the least electronegative atom

Rule 3: Count the total number of valence electrons, including charges

Rule 4: Place electron pairs between each atom to represent a single covalent bond, then distribute the remainder of the electrons around the surrounding atoms (except hydrogen) to satisfy octet rule. [Any remaining electrons that have not been distributed can be placed on the central atom as lone pairs]

Rule 5: Replace electrons with lines to represent bonds and place square brackets around the final structure. Indicate the charge on the structure by placing the charge on the outside of the right square bracket.

Question 5

IF OCTET IS NOT SATISFED ON CENTRAL ATOM WHAT SHOULD YOU DO?

Answer 5

Should an octet not be satisfied on central atom, non-bonding electrons on the outer atoms can be used to create a double bond

Question 6

HOW TO KNOW IF YOUR LWIS STRUCTURE IS CORRECT?

Answer 6

1. FULL SHELL
2. TOTAL # OF E- ARE CORRECT
3. Structure has the proper overall shape (everything is spread out as far apart as possible around the central atom – remember that lone pairs and bonds take up the same amount of space!)
   If the central atom has two lone pairs, remember to put them adjacent to each other!

Question 7

What is a molecular compound that is an expception to the octet rule?

Answer 7

nitrogen dioxide, NO2
No matter how you draw it, there’s always one atom that doesn’t have a full octet!

Question 8

Properties of molecular compounds

Answer 8

tSolid, liquid, or gas
weaker interactions with each molecule causes them to be Solids can be soft, waxy, flexible, or crystalline
Relative melting/boiling point: Lower than ionic
Solubility in water: Some good, some poor
Electrical conductivity as a solid: Low or none
Electrical conductivity when dissolved in water (aqueous): Low or none