Structure 2.2

Question 1

When are covalent bonds formed?

Answer 1

When electrons from different atoms are shared so that each atom attains a noble gas electron configuration (full valence shell). Known as the octet rule.

Question 2

Single covalent bond

Answer 2

When one pair of electrons is shared between two atoms

Question 3

Double covalent bond

Answer 3

Two pairs of shared electrons

Question 4

Triple covalent bonds

Answer 4

Three pairs of shared electrons

Question 5

Bond strength ___ as bond length decreases, as the number of shared pairs of electrons ___

Answer 5

increases, increases

Question 6

The greater the number of shared pairs of electrons, the ___ the attraction between the two covalently bonded atoms

Answer 6

greater

Question 7

Coordination covalent bonds

Answer 7

Covalent bonds where both the shared electrons come from the same atom

Question 8

Arrows in lewis diagrams signify…

Answer 8

coordination covalent bonds

Question 9

What is an incomplete octet?

Answer 9

An exception to the octet rule where atoms are stable with fewer than 8 electrons in their valence shell. This usually happens with elements like boron (6val e) and beryllium (4val e).

Question 10

Electron deficient

Answer 10

Electron deficient describes molecules or atoms that don’t have enough electrons to achieve a full octet around one or more atoms. These molecules often contain atoms like boron or beryllium, which are stable with fewer than 8 electrons.

Question 11

Electronegativity

Answer 11

A relative measure of the attraction an atom has for a shared pair of electrons when it is covalently bonded to another atom

Question 12

Trend in electronegativity values

Answer 12

They increase across a period and up a group. Most electronegative elements are F, O and N. H is similar to C

Question 13

What is the polarity of a covalent bond between two atoms of the same element?

Answer 13

Non-polar as the bonding pair of electrons is shared equally between the two atoms

Question 14

What results in a polar bond?

Answer 14

A covalent bond between two different types of atoms. The more electronegative atom will attract the bonding pair of electrons making that atom the negative dipole.

Question 15

What happens if the difference in electronegativity between the two covalently bonded atoms is greater than 1.8?

Answer 15

The bonding pair of electrons moves completely towards the more electronegative atom and the bonding becomes ionic.