Chapter 8: Basic Concepts of Chemical Bonding

Question 1

What is a covalent bond?

Answer 1

A covalent bond refers to a pair of shared electrons between two atoms (2 nonmetals usually.)

Question 2

What is the relationship on the PTE in regards to electronegativity?

Answer 2

L-R and D-U is an increase in electronegativity.

Question 3

What group is the only except to the rules of electronegativity in regards to the PTE?

Answer 3

Noble gases

Question 4

What is the most electronegative element?

Answer 4

Fluorine

Question 5

What is least electronegative element?

Answer 5

Cesium and Francium

Question 6

What defines the polarity of a molecule?

Answer 6

The bigger the difference in electronegativity between two atoms, the more polar the bond.

Question 7

What range must the difference in polarity be in order for a molecule to be considered “Purely covalent?”

Answer 7

0<0.4

Question 8

What range in difference of electronegativity encompasses the “polar covalence?”

Answer 8

.4<1.6

Question 9

What range is considered ionic?

Answer 9

x>1.6

Question 10

What happens to the electronegativity when an element loses an electron?

Answer 10

The electronegativity becomes more negative, meaning less electronegativity, meaning it is more likely to share electrons with other elements.

Question 11

What is lattice energy?

Answer 11

The energy associated with electrostatic interactions. It is governed by Coulomb’s Laws.

Question 12

Define the terms in the following equation for Lattice Energy: Ele = k (Q1Q2/d)

Answer 12

Eel = Lattice Energy
k = 8.99x10^9J*M/C
d = distance from the nucleus of one atom to the other
Q1 /2 = Charges on both atoms/elements

Question 13

The greater the difference in electronegativity, the more _____ the bond.

Answer 13

Polar

Question 14

How does one decide which atom becomes the central atom of a molecule?

Answer 14

It is the least electronegative and/or has the highest capacity to share electrons.

Question 15

Define “Electron affinity”

Answer 15

The amount of energy released when an electron is added to an element or atom.

Question 16

The 6 steps for drawing Lewis Structures

Answer 16

1. Count up formal charges, adding one if the molecule is a negative ion and subtracting if it is positive.
2. Determine the central atom based on which atom has the lowest EN and highest bonding sites
3. Fill the octets of the outermost atoms first.
4. Put the remaining electrons on the central atom in pairs
5. If you run out of electrons before the central atom has a complete octet, start forming multiple bonds.
6. If a central atom has more than an octet, it is okay if it’s in the third period or beyond
7. Optimize the formal charge

Question 17

How many valence electrons does Boron have?

Answer 17

6, for some reason.

Question 18

How does one calculate formal charge?

Answer 18

of VE - (# of paired, non-bonded electrons + # of bonds)

Question 19

What is the typical behavior of metals and their electrons?

Answer 19

They tend to get rid of electrons to become a positive ion.

Question 20

Covalent bonds are more common amongst _________ and __________ and are, thus, more likely to _____ electrons.

Answer 20

metals and metalloids are more likely to share electrons.

Question 21

Halogens are generally attracted to ____ _____, which means energy is required to ________ them.

Answer 21

each other and energy is required to separate them.

Question 22

Exceptions to the octet rule

Answer 22

1. Odd number of electrons
2. Less than an octet.
3. Atom in the third period and beyond.