Bonding & Structure

Question 1

Why do elements combine?

Answer 1

Atoms of elements from group 1-17 form bonds (chemically combined) to achieve a completely filled valance shell

Question 2

Properties of Metals

Answer 2

(1-3 valence electrons )
Have few valence electrons
Have a *tendency to lose valence electrons to achieve a completely filled valence shell

Question 3

Properties of non-metals

Answer 3

(4-8 valence electrons)
More valance electrons
Tendency to gain electrons to achieve a completely filled valence shell
Can also share valence electrons to achieve a completely filled valence shell -> covalent bonds

Question 4

Why are group 18 elements chemically unreactive?

Answer 4

Atoms of noble gases have a completely filled valence shell. Hence, these elements do not need to form bonds, by transferring or sharing valence electrons either atoms of other elements.

Question 5

Ionic bond

Answer 5

Strong electrostatic forces of attraction between the oppositely charged ions

Question 6

Covalent bonding

Answer 6

Sharing of valence electrons between atoms of non-metals to form simple molecules & macromolecules

Question 7

Explain in terms of structure & bonding, why NaCl has a high melting point of 80

Answer 7

large amounts of energy is needed to overcome the strong electrostatic forces of attraction between oppositely charged ions

Question 8

Explain why CO2 has a low melting point of -56.6

Answer 8

small amounts of energy is needed to overcome the weak intermolecular forces between CO2 molecules

Question 9

Can an ionic compound in solid state conduct electricity?

Answer 9

Solid ionic compound cannot conduct electricity because the oppositely charged ions are held in fixed positions in the structure.s

Question 10

Can an ionic compound at liquid/aqueous state conduct electricity?

Answer 10

Yes. as there is free mobile ions in the structure.

Question 11

Can a simple covalent compound conduct electricity?

Answer 11

Simple molecules are electrically neutral, they will not conduct electricity in solid, liquid or gaseous state

Question 12

Are ionic compounds soluble in water?

Answer 12

Generally yes.
Dissociates in water

Question 13

Are covalent compounds soluble in water?

Answer 13

Generally no.
Insoluble in water

Question 14

Liquid to gaseous state for CO2

Answer 14

Energy gained by CO2 to overcome intermolecular forces of attraction between CO2 particles

Question 15

Giant ionic lattice structure

Answer 15

Made up of oppositely charged ions & strong electrostatic forces of attraction between ions