Periodic table

Question 1

What is a group in the periodic table?

Answer 1

A column of elements with similar properties and the same number of outer shell electrons

Question 2

What is a period in the periodic table?

Answer 2

A horizontal row. Elements show trends in properties across a period.

Question 3

What is periodicity?

Answer 3

The regular repeating pattern in properties of the elements across different periods

Question 4

How is a subshell different from an orbital?

Answer 4

A subshell is a group of the same type of orbitals.

Orbitals are regions of an atom containing up to 2 electrons with opposite spins. (s orbitals are spherical in shape, p orbitals are dumbbell shaped.)

Question 5

How many electrons can an orbital hold?

Answer 5

2

Question 6

Which has a higher energy level, an N d orbital or an N+1 s orbital

Answer 6

The d orbital

Question 7

How are noble gas electron configurations shown

Answer 7

[Noble Gas} Then electron config from that level

Question 8

What is first ionisation energy?

Answer 8

The energy required to remove one electron from each atom in one mole of gaseous atoms (to form 1 mole of gaseous 1+ ions)

Question 9

What is the first i.e. equation of any element, X?

Answer 9

X(g) —> X+(g) + e-

Question 10

What is the general trend in first i.e. across a period?

Answer 10

Increases

Question 11

How does first ionisation energy change down a group?

Answer 11

Decreases

Question 12

Why do the first ionisation energies drop sharply between the Group 0 element of one period to the Group 1 element of the next period?

Answer 12

The electrons are being removed from a new outer shell.

Question 13

What are the four factors effecting first i.e. ?

Answer 13

i. Nuclear charge (number of protons)
ii. Shielding (number of shells)
iii. Atomic radius
iv. Nuclear attraction

Question 14

What points on a first i.e. graph do not obey the general trend and why?

Answer 14

2 –> 3 - The fall between groups 2 and 3 marks the start of filling the p subshell. In Be, the outer electron is in a 2s orbital, in B the outer electron is in a 2p orbital.

The 2p orbital in B is of higher energy and experiences more shielding from inner electrons, as it is also shielded by the electrons in the 2s subshell.

Despite the fact that the nuclear charge increases by +1 from Be to B, the difference in shielding and energy means the nuclear attraction is weaker in B, so less energy is required to remove it’s outer electron.

5 –> 6 - The fall between groups 5 and 6 marks the start of electron paring in the p-orbitals in the p-subshell. In N, the outer electron is unpaired in a 2p orbital, in O the outer electron is paired in a 2p orbital.

The paired electrons in oxygen repel slightly, making it easier to remove an electron than in nitrogen.

Question 15

How do group 2 metals react with oxygen? Let M be the metal

Answer 15

2M (s) + O2 (g) –> 2MO (s)

Question 16

How do group 2 metals react with water? Let M be the metal

Answer 16

M(s) + 2H2O (L) —> M(OH)2 + H2

Metal + Water —> Metal hydroxide + H2

Question 17

How do group 2 metals react with acid? Let M be the metal

Answer 17

M(s) + HCl2 (aq) —> MCl2 (aq) + H2O

Metal + Acid —> Salt + Water

Question 18

What does a reaction need to be balanced?

Answer 18

Same number of atoms on both sides
Same charge on both sides
Same oxidation number total on both sides

Question 19

What does phenolphthalein indicator do?

Answer 19

Turns pink in alkaline solutions

Question 20

How does the sum of the first and second IEs tell you about how reactive the metal is with water?

Answer 20

The higher the sum of the first and second I.E, the higher the temperature of the water has to be before reacting

Question 21

How do group 2 metal oxides react with water? Let M be the metal. What would be seen when this reaction occurs?

Answer 21

MO + H2O —> M(OH)2

Metal oxide dissolves —> White solid forms

Question 22

What is solubility?

Answer 22

A measure of the ability of a solute to dissolve in a solvent.

Question 23

What is alkalinity?

Answer 23

A measure of the concentration of hydroxide ions, OH-(aq) present in an alkaline solution.

Question 24

How do the solubility, alkalinity and pH of the group 2 hydroxides change down the group?

Answer 24

They increase

Question 25

How is the solubility of the metal hydroxides related to their alkalinity?

Answer 25

The more soluble the hydroxide the more OH- ions are present in the solution, so the more alkaline the solution is.

Question 26

What colours are:
Chlorine 
Bromine
Iodine
At room temperature?

Answer 26

Chlorine = Green
Bromine = Brown (with orange vapour)
Iodine = Grey

Question 27

What is the trend in boiling point as you go down group 7?

Answer 27

Increases

Question 28

Of Cl, Br and I which has the strongest covalent bond and why?

Answer 28

Chlorine because in each halogen, the covalent bond is formed by a pair of electrons between the atoms attracting the nuclei of these atoms. The closer the electrons are to the nucleus, the stronger the attraction.

In addition, the smaller atoms have more condensed electron cloud with a higher charge density. This also leads to stronger bonding.

Question 29

Why are negative ions larger than the corresponding atoms?

Answer 29

Because accepting an electron increases the repulsion, pushing the e- slightly further out

Question 30

What colours are:
Chlorine 
Bromine
Iodine
In water?

Answer 30

Chlorine = Very pale green 
Bromine = Orange
Iodine = Orange

Question 31

What colours are:
Chlorine 
Bromine
Iodine
In hexane?

Answer 31

Chlorine = Pale green
Bromine = Orange
Iodine = Purple

Question 32

What is a disproportionation reaction?

Answer 32

A reaction where the same element is both oxidised and reduced.