Lesson 2- Atoms, bonding And Polarity

Question 1

Isotopes

Answer 1

• Atoms of the same element that vary by the number of neutrons
• Since they have the same number of electrons, all isotopes of an element usually have the same chemcial properties

Question 2

Why are electrons important?

Answer 2

• The chemical behaviour of an atom is determined by its electron configuration
• Outermost shell —> valence electron/shell
• Atoms with incomplete valence shells are usually reactive

Question 3

Chemical bond: Intramolecular

Answer 3

• Formed by the sharing or transfer of electrons
• Two types of chemical bonds: Ionic, Covalent

Question 4

Ionic

Answer 4

Transfer of ions

Question 5

Cations, Anions, Ionic bonds, Octet rule

Answer 5

Cations- Positively charged ions

Anions- Negatively charged ions

Ionic bonds- Occur when one atom donates or gives up one or more electrons

Octet Rule- Atoms tend to gain, lose or share electrons to have 8 valence electrons

Question 6

Covalent Bonding

Answer 6

Involves the sharing of a pair of electrons between atoms

Question 7

Polarity

Answer 7

• Sharing of electrons
• Separation of electric charge

Question 8

Two types of Covalent Bonds

Answer 8

Polar Covalent

Non-Polar Covalent

Question 9

Polar Covalent, give examples

Answer 9

Unequally sharing of electrons

Eg. H2O, HCl

Question 10

Non-Polar Covalent, give examples

Answer 10

Equal sharing of electrons

Eg. H2, CO2

Question 11

How are types of covalent bonds determined?

Answer 11

Electronegaticity and symmetry

Question 12

Electronegativity

Answer 12

• The relative ability to attract electrons
• Higher Electronegativity = Stronger pull of shared electrons

Question 13

Electronegativity range

Answer 13

0-5 - 1.7 is Polar

Less than or equal to (<_ ) 0.5

Question 14

Dipoles

Answer 14

• Charge due to unequal sharing of electrons