Electrons, Bonding and Structure

Question 1

How many electrons fill each shell?

Answer 1

1st shell - 2
2nd shell - 8
3rd shell - 18
4th shell - 32

Question 2

Describe the energy levels of shells

Answer 2

Electrons further from the nucleus are in a higher energy state
the order of subshells is s, p, d and f

Question 3

What are the shapes of the subshells

Answer 3

s - spherical
p - dumbbell

Question 4

What are the max num of electrons in each sub-level

Answer 4

s - 2
p - 6
d - 10
f - 14

Question 5

What are orbitals

Answer 5

regions of space that electrons are most likely to be in

Question 6

What is the Aufbau Principle

Answer 6

Easier to sit downstairs than upstairs
- lower levels are filled before the higher levels

Question 7

What is Hund’s rule

Answer 7

Prefer to sit on an empty seat than one with someone in it
- half fill the orbitals of the same energy with electrons of the same spin

Question 8

What is Pauli’s Exclusion Principle

Answer 8

Electrons must have different spins

Question 9

What is Ionic Bonding

Answer 9

The electrostatic attraction between positive and negative ions

Question 10

Why do ions form

Answer 10

Because atoms gain or lose an electron to become isoelectronic with a noble gas
- noble gases have a full valance shells, making them stable

Question 11

Why do Ions dissolve in water

Answer 11

Water is polar and so the positive ion is attracted to Oxygen and the negative ion is attracted to Hydrogen

Question 12

What does isoelectronic mean

Answer 12

Same number of electrons

Question 13

What is a covalent bond

Answer 13

The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 14

What are the properties of covalent

Answer 14

Low m.p and b.p - weak intermolecular forces
Good insulators - neutral and no free charge
Soluble in non-polar solvents

Question 15

What is dative bonding

Answer 15

Occurs when an atom shares a lone pair of electrons to form a bond

Question 16

What shape and angle would a bond with 2 bonding pairs and 0 lone pairs

Answer 16

Linear - 180 degrees

Question 17

What shape and angle would a bond with 3 bonding pairs and 0 lone pairs

Answer 17

Trigonal planar - 120 degrees

Question 18

What shape and angle would a bond with 4 bonding pairs and 0 lone pairs

Answer 18

Tetrahedral - 109.5 degrees

Question 19

What shape and angle would a bond with 5 bonding pairs and 0 lone pairs

Answer 19

Trigonal Bipyramidal - 120 + 90 degrees

Question 20

What shape and angle would a bond with 6 bonding pairs and 0 lone pairs

Answer 20

Octahedral - 90 degrees

Question 21

What shape and angle would a bond with 2 bonding pairs and 1 lone pair

Answer 21

Non-linear - 117.5 degrees

Question 22

What shape and angle would a bond with 2 bonding pairs and 2 lone pairs

Answer 22

Non linear - 104.5 degrees

Question 23

What shape and angle would a bond with 3 bonding pairs and 1 lone pair

Answer 23

Pyramidal - 107

Question 24

What shape and angle would a bond with 4 bonding pairs and 2 lone pairs

Answer 24

Square planar - 90 degrees

Question 25

What is electronegativity

Answer 25

The ability of an atom to attract the bonding electrons in a covalent bond

Question 26

What does a greater electronegativity mean

Answer 26

greater pull

Question 27

What is the Pauling scale

Answer 27

The electronegativity scale that shows that electronegativity increases across a period and up a group

Question 28

Why does electronegativity increase across a period

Answer 28

Increase in protons means a higher nuclear charge

Question 29

Why does electronegativity increase up a group

Answer 29

Less electron sheiding

Question 30

What are dipoles

Answer 30

Occur when electrons are shared unequally due to the electronegativity of an element

Question 31

What are Polar molecules

Answer 31

Polar molecules occur if the bond dipoles can’t cancel out, thus giving the
overall molecule a dipole.

Question 32

What are the 3 intermolecular forces

Answer 32

Permanent dipole-dipole interactions
Induced dipole-dipole interactions
Hydrogen bonding

Question 33

What is Permanent Dipole-dipole interactions

Answer 33

The weak electrostatic attraction between two polar molecules

Question 34

What is Induced Dipole-Dipole interaction

Answer 34

Happens in all molecules
Electrons move closer to one side of the electron, creating a δ– charge
This can then induce a dipole in another nearby molecule - instantaneous-induced dipole interaction

Question 35

What is the order of intermolecular forces (strongest to weakest)

Answer 35

Hydrogen
Permanent dipole-dipole
Induced dipole-dipole

Question 36

Simple molecule structure

Answer 36

simple molecular lattice with molecules arranged in a repeating pattern, held together by weak induced dipole-dipole forces
when heated the weak intermolecular forces are easily broken, allowing molecules to escape as gas

Question 37

Which molecules undergo sublimation

Answer 37

CO2 and I2

Question 38

What is hydrogen bonding

Answer 38

intermolecular bonding between molecules containin N,O or F and the H atom of -NH, -OH, or HF

Question 39

What is needed for hydrogen bonding to occur

Answer 39

a lone pair of electrons
a hydrogen covalently bonded to a F, O or N atom

Question 40

What are the anomalous properties of water

Answer 40

Less dense as a solid
Relatively high m.p. and b.p

Question 41

Why is water less dense as a solid

Answer 41

Liquid water
– hydrogen bonds constantly broken and reformed.

Solid water
– molecules arranged in hexagonal rings to maximise the number of
stable hydrogen bonds.
- creating a larger volume

Question 42

What is metallic bonding

Answer 42

Metal-metal bonds held together by strong electrostatic forces of attraction between delocalised electrons and positive ions