Chemical Bonding Part 1

Question 1

Give the two reasons atoms bond and why? (2x3)

Answer 1

• To obtain noble gas electron structures

Want the outer most energy levels to be full = increase in stability and no more chemical bonding

• To obtain a lower state of energy

Energy is released to form chemical bonds.
Formations allow atoms to achieve a lower energy level

Question 2

What is Chemical Bonding (3)

Answer 2

Chemical bonding is the process by which atoms bond with each other and in this way achieve a noble gas configuration, with low potential energy

Question 3

What is a molecule? (2)

Answer 3

A molecule is a group of two or more atoms which are bonded together strongly enough to behave as a single unit in a chemical reaction

Question 4

A bonded state is known to be? (1)

A non bonded state is also known as… (1)

Answer 4

• More stable state

- “free state”not stable

Question 5

What are between chemical bonds? (3) #

Answer 5

• Must be forces to form such a unit
• A mutual binding force = chemical bonding
• Both attractive and repulsive forces between the atoms

Question 6

Two ways atoms attract to each other (2) #

Answer 6

• Nucleus (+) with its own electrons (-)

- Nucleus (+) with other atoms electrons (-)

Question 7

2 ways the atoms repel (2) #

Answer 7

• Nucleus (+) with other nucleus (+)

- Electrons (-) with other electrons (-)

Question 8

How do bonds form? (1) #

Answer 8

When forces of attraction = forces of repulsion

Question 9

What is bond length? (2) #

Answer 9

• The distance between the nuclei of the atoms

- The lowest energy point, where the atoms want to be

Question 10

How does energy change in an atom? (2) #

Answer 10

Attraction - work more over a long distance

Repulsion - work more over a short distance

Question 11

Point at which atoms are far apart is taken advantage? (1) #

Answer 11

0

Question 12

What is bond strength? (2) #

Answer 12

Bond strength is the amount of energy needed to break a chemical bond

Question 13

Bond strength and length are… (1) #

Answer 13

• Inversely related

Question 14

Bond strength points (3) #

Answer 14

• measured in joules
• weak bonds easily broken
• strong bonds hard to break

Question 15

Decimeter (2) #

Answer 15

• dm

- 10^-1m

Question 16

Centimeter (2) #

Answer 16

• cm

- 10^-2m

Question 17

Millimeter (2) #

Answer 17

• mm

- 10^-3m

Question 18

Micrometer (2) #

Answer 18

• um (curved u)

- 10^-6m

Question 19

Nanometer (2) #

Answer 19

• mm

- 10^-9m

Question 20

Picometer (2) #

Answer 20

• pm

- 10^-12m

Question 21

What is valency? (2)

Answer 21

Valency is the measure of the number of chemical bonds formed by the atoms of a given element

Question 22

Calculating valency: 
Groups 1-4 = 
Groups 5-8 = 
Charge of ion =
Roman numerals = 
Zinc =
Silver =

Answer 22

= group number
= 8 - group number
= valency
= valency
= 2
= 1

Question 23

What group is the exception to the Lewis structure? (1)

Answer 23

Group 4 (1 on each side)

• Carbon
• Silicon

Question 24

Elements don’t gain electrons to become noble gases. They… (1)

Answer 24

They gain noble gas electron STRUCTURES

Question 25

Atoms can gain noble electron structures in 3 ways (3)

Answer 25

• Share electrons
• Gain electrons
• Donate electrons

Question 26

3 types of bonding (3)

Answer 26

• Covalent
• Metallic
• Ionic

Question 27

What is Covalent bonding? (2)

Answer 27

Covalent bonding is a sharing of electrons between two non-metal atoms, forming a molecule

Question 28

4 points on a covalent bond (4)

Answer 28

• Generally occurs between 2 non-metals
• It is the sharing of electron pairs
• Product is called a molecule
• Shared pair of electrons = bonding pair

Question 29

Unshared pairs of valence electrons are known as…

Answer 29

Lone pairs

Each electron must have opposition spin

Question 30

What is Electronegativity? (2)

Answer 30

Electronegativity is an indication of the attraction that an atom exerts on a shared electron pair

Question 31

What is the bonding force?

Answer 31

The coulombic attraction between the nuclei (+) and the electrons (-)

Question 32

Why does Helium not form He2? (1)

Answer 32

Because it is already a noble gas with a filled up valence electron structure

Question 33

Why do noble gases not have Electronegativity? (1)

Answer 33

They don’t share electron pairs because they don’t bond

Question 34

Fluorine has the highest Electronegativity. Why? (1)

Answer 34

It has a very strong attraction for a shared electron pair

Question 35

What is a non polar covalent bond? (2)

Answer 35

A non polar covalent bond (pure covalent bond) is a covalent bond where there is an equal sharing of electrons

Question 36

What is a polar covalent bond? (2)

Answer 36

A polar covalent bond is a covalent bond where there is an unequal sharing of electrons leading to a dipole forming (as a result of Electronegativity difference)

Question 37

Delta means what (3)

Answer 37

• a change in something
• bigger delta shown as a triangle
• small shown as an sd

Question 38

Explain the difference in Electronegativity? (3)

Answer 38

When the electronegativity is 0 = Non Polar Covalent Bond
When bigger than 0 but smaller than 2,1 = Polar Covalent Bond
When bigger than 2,1 = Ionic Bond

Question 39

What is a dipole? (1)

Answer 39

A dipole is the separation between two covalently bonded atoms

Question 40

Give me an example of dipoles (2)

Answer 40

• HCl
• H has a lower Electronegativity so it gets the - delta
• Visa Versa

Question 41

What is the polarity of a bond? (3)

Answer 41

• The bond dipole
• Indicated by an arrow
• Points towards more electronegative side