2.2 Electrons & Bonding Structure

Question 1

What are the 4 orbitals and how many electrons can they each contain

Answer 1

• S= 2 = sphere shape
• P= 6 = 3 dumbbell shapes
• D= 10
• F = 14

Question 2

How do electrons behave in orbitals?

Answer 2

the 2 electrons in an orbital must have opposite spin to prevent them repelling eachother

Question 3

How do electron shells fill

Answer 3

added one at a time from lowest energy, previous orbital must be filled to move onto next

Question 4

What are the unique properties of the 4s orbital

Answer 4

slightly lower energy level than 3d so fills up first,

however also loses electrons first

Question 5

What are the 3 main types of bonding

Answer 5

• Ionic (between metals & non metals)
• Covalent (between non metals)
• Metallic (between metals)

Question 6

What happens in Ionic Bonding

Answer 6

Electrons transferred form metal to non metal atoms
Metal=positive(cation)
Non metal=negative (anion)

Question 7

What happens in Covalent Bonding

Answer 7

Electrons shared between bonded non metal atoms

Question 8

What happens in Metallic Bonding

Answer 8

Electrons shared between all metal atoms

Question 9

What are giant ionic lattices

Answer 9

When each ion is attracted to surrounding opposite ions and they form a lattice with lots of electrostatic attraction

Question 10

List the properties of an Ionic compound

Answer 10

• High melting & boiling point
• conduct electricity if molten
• dissolve in polar solvents (due to small charges on polar molecules attraction ions)

Question 11

What are lone pair electrons, what affect do they have?

Answer 11

A pair of electron not used in bonding, give concentrated regions of negative charge

Question 12

What are the differences between single and multiple covalent bonds

Answer 12

single- one electron from each atom

multiple- sharing more than one pair of electrons

Question 13

What’s a dative covalent bond

Answer 13

When the electrons in a covalent bond come from only one of the bonded atoms

Question 14

What’s Average bond enthalpy

Answer 14

the average energy required to break a covalent bond

Question 15

How is the octet rule changed in A level chem

Answer 15

8 electrons not actually needed for ‘full’ outer shell
• unpaired electrons pair up
• the max amount of electrons that can pair is the amount in outer shell

Question 16

What are the feature of a simple molecular structure

Answer 16

strong covalent bonds between atoms but molecules held by weak intermolecular forces
• low melting & boiling points
• No conductive
• generally soluble in non polar solvent

Question 17

What are the feature of a Giant covalent structure

Answer 17

• High Melting & boiling points
• Non conductive, except Graphite
• insoluble as bonds too strong

Question 18

What is electron pair repulsion theory?

Answer 18

as all electrons have negative charge they repel eachother, so molecular shapes allow electrons to be as far from each other as possible

Question 19

Linear (1or 2) shaped bond angle?

Answer 19

180°

Question 20

Trigonal planar (3) bond angle?

Answer 20

120°

Question 21

Tetrahedral (4) bond angle?

Answer 21

109.5°

Question 22

Pyramidal (4) bond angle, why?

Answer 22

107°, due to the lone pair electrons causing slightly more repulsion

Question 23

Trigonal bipyramidal (5) bond angle?

Answer 23

2 90° and 3 120°

Question 24

Octahedral (6) bond angle?

Answer 24

90°

Question 25

What is Electronegativity

Answer 25

Measure of attraction to electrons shared between bonded atoms in a covalent bond

Question 26

What are Polar bonds?

Answer 26

When covalently bonded atoms have large differences in electronegativity and so one atom attract the electrons more causing small charges (permanent dipoles)

Question 27

Why must molecules with polar bond be NON-symmetrical for the molecule to be considered polar?

Answer 27

If the molecule has symmetrical polar bonds, the dipoles may cancel eachother out resulting in a non polar molecule

Question 28

What are Intermolecular forces

Answer 28

The forces that act between molecules/compounds as compared to those that hold together atoms

Question 29

What are the the two types of intermolecular forces

Answer 29

* Hydrogen | * Vanderwalls forces( London forces & dipoles)

Question 30

What's a permanent dipole-induced dipole interaction

Answer 30

When polar(with permanent dipole) molecule meet non polar molecules and cause it to become slightly polar

Question 31

What's a permanent dipole-permanent dipole interaction

Answer 31

When two polar molecules meet and the opposite partial charges from the different molecule attract

Question 32

What are London(dispersion) forces

Answer 32

when random electron movement causes imbalance in distribution and form instantaneous dipole that induce dipoles on neighbouring molecules, which attract eachother

Question 33

How does the number of electrons the non-polar molecule has affect London forces

Answer 33

More electrons= larger induced dipole= more attraction

Question 34

What's a hydrogen bond

Answer 34

Bond between very electronegative elements and hydrogen

Question 35

How do hydrogen bonds affect water

Answer 35

* Higher melting & boiling points than expected * Ice less dense than water * high surface tension & viscosity

Question 36

UNCERTAINTY eq

Answer 36

(absolute uncertainty *2)/ value measured