4.2 Covalent Bonding

Question 1

Why do substances form covalent bonds?

Answer 1

It’s when two non-metals react together to both gains electrons into order to get a stable structure of a noble gas

Question 2

What’s a molecule?

Answer 2

A group of atoms which are held together by covalent bonds

Question 3

Why are the atoms in a covalent bond a fixed distance apart?

Answer 3

The forces of attraction are balanced by the repulsion between the two nuclei

Question 4

The tendency to form a ………….. Arrangement is called the ……… Rule

Answer 4

The tendency to form a stable arrangement is called the octet rule

Question 5

The pairs of electrons which aren’t involved in the bonding are called?

Answer 5

Lone pairs or non-bonding pairs

Question 6

What do lone pairs do?

Answer 6

Determine the shape of the molecule

Question 7

What is a covalent bond?

Answer 7

An electrostatic attraction between a shared pair of electrons and a positively charged nuclei

Question 8

How is a double bond formed?

Answer 8

When two pairs (4 electrons) are shared to make a complete octet

Question 9

How is a triple bond formed?

Answer 9

When 3 pairs (six electrons) are shared to make a complete octet

Question 10

What is a sigma bond?

Answer 10

The first bond

Question 11

What is a pi bond?

Answer 11

The second bond that is slightly weaker than the first one

Question 12

What is bond length?

Answer 12

A measure of the distance between the two bonded nuclei

Question 13

What is bond strength?

Answer 13

A measure of the energy it takes in order to break the bond

Question 14

As the ………… Radii increased the molecules form ……….. Bonds

Answer 14

As the atomic radii increases the molecules form longer bonds

Question 15

What is the relationship between bond length and strength?

Answer 15

As the bond gets longer the pair of electrons are further from the nuclei meaning the bonds are weaker

Question 16

What makes bond length shorter?

Answer 16

Multiple bonds have a greater number of shared electrons and therefore have a stronger electrostatic attraction between the nuclei, which pulls the nuclei closer together and makes a shorter bond length

Question 17

Why do polar bonds occur?

Answer 17

They are the result of unequal sharing of electrons, when the electronegativity values are very different which gives one of the atoms more possession of the electrons - this makes the bond unsymmetrical and the molecules becomes polar

Question 18

What is a dipole?

Answer 18

A bond with separated opposite charges

Question 19

What is the relationship between electronegativity and the periodic table?

Answer 19

The electronegativity increases across a period and decreases down a group with Fluorine being the most electronegative element

Question 20

Are there bonds which are completely non-polar?

Answer 20

There are only a few bonds which are truly non polar, F2, H2 and O2 because their difference in electronegativity is 0 a.k.a pure covalent