Mod 2 Chapter 5

Question 1

Maximum number of electrons in each shell formula?

Answer 1

2n^2

Question 2

As shell number increases

Answer 2

Energy increases (as shells are fixed energy levels)

Question 3

What is the principal quantum number?

Answer 3

Shell number/energy level number

Question 4

What is an atomic orbital?

Answer 4

Region around nucleus that can hold up to two electrons with opposite spin (high probability of finding an electron)

Question 5

How many electrons can orbitals hold?

Answer 5

S, p, d and f can hold up to 2 electrons with each orbital having a different shape

Question 6

Why do electrons have opposite spins?

Answer 6

To prevent repulsion

Question 7

S-orbitals

Answer 7

Electron cloud in shape of a sphere and each shell from n=1 contains 1 s-orbital ; greater the shell number, greater the radius of its s-orbital

Question 8

P-orbitals

Answer 8

Shape of a dumbell (x, y and a) ; one orbital can contain max 2 electrons BUT there are 3 p orbitals at right angles to one another therefore each shell from n=2 contains 3 p-orbitals

Question 9

The greater the shell number n

Answer 9

Further the p-orbital is from the nucleus

Question 10

D orbitals

Answer 10

Each shell from n=3 contains 5 d-orbitals

Question 11

F orbitals

Answer 11

Each shell from n=4 contains 7 f-orbitals

Question 12

What are sub shells?

Answer 12

Orbitals of the same type grouped together

Question 13

How many electrons can fit in the p subshell?

Answer 13

3*2 = 6 electrons

Question 14

How many electrons can fit in the d subshell?

Answer 14

5*2 = 10

Question 15

How many electrons can fit in the f subshell?

Answer 15

7*2 = 14

Question 16

What is important to note with the filling of the 3rd and 4th shell?

Answer 16

Highest energy level of 3rd shell (3d subshell) overlaps the lowest energy level in the 4th shell (4s subshell) - THEREFORE 4S SUBSHELL FILLS BEFORE 3D AND LOSES ELECTRONS BEFORE 3D

Question 17

Why do electrons have opposite spins?

Answer 17

Electrons are negatively charged and repel one another - therefore there spin is needed to help counteract the repulsion between the negative charges of the two electrons

Question 18

How do electrons occur subshells?

Answer 18

If there is more that one orbital in subshell, then one electron occupies each orbital and only then can pairing take place with opposite spin

Question 19

Electron configuration of Krypton?

Answer 19

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6

Question 20

How can shorthand electron configuration be expressed?

Answer 20

Previous noble gas in the table + the outer electron sub shells (useful for emphasising the similarities in electron configuration of outer shell - same last number of each element in group)

Question 21

Cations

Answer 21

Positive ions - lose electrons

Question 22

Anions

Answer 22

Negative ions - gain electrons

Question 23

S-block

Answer 23

Highest energy electrons in the s-sub-shell (block of two groups)

Question 24

P-block

Answer 24

Highest energy electrons in the p-sub-shell (right block of six groups)

Question 25

D-block

Answer 25

Highest energy electrons in the d-sub-shell (centre block of 10 groups)

Question 26

What happens to electron configuration with ions?

Answer 26

Highest energy sun-shells lose or gain electrons (4s loses before 3d)

Question 27

How to form electron configuration of Ni2+ ; Ni has 28 electrons

Answer 27

4s FILLS FIRST Once full, 3d energy falls below that of 4s therefore 4s loses first as well Nickel atom : 1s2 2s2 2p6 3s2 3p6 3d8 4s2 Ni2+ atom : 1s2 2s2 2p6 3s2 3p6 3d8

Question 28

2 exceptions to electron configuration?

Answer 28

Chromium and Copper ; 3d does want to be half or fully full therefore 1 electron is taken from 4s2

Question 29

What is ionic bonding?

Answer 29

Electrostatic attraction between positive and negative ions (holding together cations and anions in ionic compounds)

Question 30

Structure of ionic bonding?

Answer 30

Each ion attracts oppositely charged ions in all directions - resulting in a giant (repeating) ionic lattice

Question 31

Features of giant ionic lattice?

Answer 31

Each metal ion is surrounded by 6 non metal ions and vice versa - this attraction between oppositely charged ions forms a giant ionic lattice

Question 32

What state are ionic compounds at room temperature?

Answer 32

Solids (high MP and BP) - at room temp there is insufficient energy to overcome strong electrostatic forces and therefore high temperatures are needed to provide the large quantity of energy needed to overcome these forces (therefore high MP and BP)

Question 33

What else affects MP and BP?

Answer 33

They are higher temperatures for lattices containing ions with greater ionic charged as there is a stronger attraction between the ions - this depends on the size of the ions

Question 34

Solubility of ions?

Answer 34

Many ions dissolve in polar solvents like water because the H2O molecules break down the lattice and surround each ion in solution

Question 35

What affects solubility of ions?

Answer 35

Large charges, which mean there is a larger ionic attraction, means that water is unable to break down the lattice structure - therefore the compound is not that soluble

Question 36

Why can ionic compounds not conduct electricity in the solid state?

Answer 36

They are in a fixed position in the giant ionic lattice and there are no mobile charge carriers

Question 37

Why can they conduct electricity when dissolved/liquid?

Answer 37

Ionic lattice breaks down with the ions now free to move - now it is a conductor of electricity in liquid and aqueous states

Question 38

What is covalent bonding?

Answer 38

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

Question 39

How are they bonded covalently?

Answer 39

A small molecule, giant covalent structure or a charged poly atomic ion

Question 40

What is the orbital overlap in covalent bonding?

Answer 40

Overlap of atomic orbitals - each contains 1 electron to give a shared pair of electrons The shared pair of electrons is attracted to the nuclei of both the bonding atoms

Question 41

What does it mean by the attraction being localised?

Answer 41

Unlike giant ionic lattices where ions attract 6 other oppositely charged ions, here the attraction is localised within the atom itself, creating a molecule - which is the smallest part of a covalent compound that can exist whilst retaining the chemical properties

Question 42

Displayed formula?

Answer 42

Relative positioning of atoms and bonds between them shown as lines - pair electrons that are not shared are lone pairs

Question 43

Number of covalent bonds usually formed by carbon, nitrogen, oxygen and hydrogen?

Answer 43

``` C = 4 N = 3 O = 2 H = 1 ```

Question 44

Expansion of the octet?

Answer 44

The outer shell of sulfur in SF6 now has 12 electrons - which is on,y possible from the n=3 shell when a d-sub shell becomes available for expansion

Question 45

What is a dative bond?

Answer 45

Covalent bond where the shared pair of electrons has been supplied by only one of the bonding atoms - this was originally a lone pair of electrons

Question 46

Draw NH4+

Answer 46

H+ means there are no electrons in hydrogen therefore nitrogen (5 in outer shell) must donate 2 of its own to hydrogen (arrow going towards hydrogen) ; they are all equivalent in magnitude and you cannot tell which is the dative bond

Question 47

Average bond enthalpy?

Answer 47

Larger enthalpy = stronger covalent bond (depends on difference in electronegativity)

Question 48

What does electron configuration show you?

Answer 48

Number of last subshell (BEFORE the letter) shows period (starts with 1 at helium/hydrogen) Last number tells you which group IN that block Last letter shows which block it is in