Bonding + Formulae

Question 1

How many electrons can each energy level hold?

Answer 1

1st energy level: 2 electrons max.
2nd, 3rd and 4th energy level: 8 electrons max.

Question 2

What is the electron arrangement of Chlorine (Cl)

Answer 2

2)8)7

Question 3

What do elements in the same group have in common?

Answer 3

The same number of outer electrons

Question 4

What makes Group 8 elements different to the other ones?

Answer 4

Group 8 elements have a full outer energy level and are chemically stable, where as Groups 1-7 are not.

Question 5

What is a covalent bond?

Answer 5

A covalent bond exists between non-metals only. These non-metals become stable by sharing electrons.

Note: make sure you know your petal diagrams

Question 6

What is the shape of a 2 atom molecule? Eg: Cl₂

Answer 6

Linear

Question 7

What is the shape of a 3 atom molecule? Eg: H₂O

Answer 7

Angular/V-Shaped

Question 8

What is the shape of a 4 atom molecule? Eg: NH ₃ / ammonium

Answer 8

Trigonal Pyramidal

Question 9

What is the shape of a 5 atom molecule? Eg: CH₄ / methane

Answer 9

Tetrahedral

Question 10

What are the two types of covalent bonds?

Answer 10

Molecules or networks

Question 11

What are the properties of covalent substances?

Answer 11

They are insoluble and they do not conduct electricity (except Cgraphite).

Question 12

What do covalent molecules generally have

Answer 12

A low m.pt/b.pt

Question 13

Why do covalent molecules have a low m.pt and b.pt

Answer 13

The have weak intermolecular forces

Question 14

Why do covalent networks have a high m.pt and b.pt

Answer 14

They have strong bonds

Question 15

What is ionic bonding?

Answer 15

Ionic bonding exists between metals and non-metals. Ionic compounds transfer electrons and they have strong bonds (electrostatic force of attraction)

Question 16

For metals to become stable in an ionic bond, what will they do?

Answer 16

Metals will always lose electrons to become stable.

Question 17

What will non-metals do in an ionic bond to become stable?

Answer 17

Non-metals will always gain electrons to become stable.

Question 18

When an atom gains/loses electrons, what are they called

Answer 18

An ion

Question 19

How would you write the ionic compound of Sodium and Chlorine

Answer 19

Na⁺Cl⁻

Question 20

What do we call the structure of an ionic compound?

Answer 20

An ionic lattice

Question 21

The chemical formulas of ionic and covalent compounds DO NOT show the amount of atoms inside it. So, what do they show?

Answer 21

A ratio of each atom.

Question 22

What are the properties of ionic compounds?

Answer 22

Most are soluble in water and form an aqueous solution.

Generally, they have high melting and boiling points.

Solid at room temperature.

Ionic compounds are colourless, unless they contain a transition metal.

Question 23

Do ionic compounds conduct electricity?

Answer 23

Ionic solids do not conduct electricity.

Ionic solutions (ie: when dissolved in water) - do conduct.

Ionic “melts” (ie: when compounds is melted into liquid and becomes molten) - do conduct.

Question 24

What is the definition of electricity?

Answer 24

Electricity is the flow of electrically charged particles.

Question 25

What are the charged particles of electricity in **metals**?

Answer 25

Electrons

Question 26

What are the charged particles of electricity in ionic compounds?

Answer 26

Ions

Question 27

Why do ionic compounds not conduct electricity when solid?

Answer 27

The ions are **not free to move** because they are held in place by **strong** bonds.

Question 28

Why do ionic compounds conduct when they are a solution or a “melt”?

Answer 28

Ions are free to move

Question 29

Give the **ionic** formula for magnesium oxide.

Answer 29

Mg²⁺O²⁻⁻

Question 30

Give the formula for magnesium chloride.

Answer 30

MgCl₂

Question 31

Give the formula for aluminium oxide.

Answer 31

Al₂O₃

Question 32

What is the definition of valency?

Answer 32

VALENCY: this is the **number of electrons** an atom needs to **lose / gain** to become **stable**.

Question 33

What is the valency of Group 1 elements?

Answer 33

1

Question 34

What is the valency of Group 2 elements?

Answer 34

2

Question 35

What is the valency of Group 3 elements?

Answer 35

3

Question 36

What is the valency of Group 4 elements?

Answer 36

4

Question 37

What is the valency of Group 5 elements?

Answer 37

3

Question 38

What is the valency of Group 6 elements?

Answer 38

2

Question 39

What is the valency of Group 7 elements?

Answer 39

1

Question 40

What is the valency of Group 8 elements?

Answer 40

0

Question 41

What is the formula for magnesium fluoride?

Answer 41

MgF₂

Question 42

What are the rules for making a formula?

Answer 42

**S**ymbols **V**alency **S**wap (if different) **D**ivide (if possible) **F**ormula

Question 43

Give the formula for aluminium carbonate

Answer 43

Al₂(CO₃)₃

Question 44

Give the formula for ammonium sulfate.

Answer 44

(NH₄)₂SO₄

Question 45

How will the valency of a transition metal be given?

Answer 45

As a Roman numeral. (ex: I, IV, VII)

Question 46

Give the formula for iron(III) chloride.

Answer 46

FeCl₃

Question 47

Give the formula for nickel(II) sulfate.

Answer 47

NiSO₄

Question 48

Dihydrogen oxide

Answer 48

H₂O

Question 49

phosphorous pentachloride

Answer 49

PCl₅

Question 50

Nitrogen dioxide

Answer 50

NO₂

Question 51

Dichromium heptaoxide

Answer 51

Cr₂O₇