1.6 Periodic Table

Question 1

how are elements arranged

Answer 1

according to atomic number

Question 2

vertical columns are

Answer 2

groups

Question 3

horizontal rows

Answer 3

periods

Question 4

trend in ionization energy across period

Answer 4

increases across a period because there is an increase in nuclear charge in the same energy level.

Question 5

ionization energy down a group

Answer 5

decreases down a group because the outer
electron has increased shielding from inner electrons.

Question 6

trend in electronegativity

Answer 6

increases across a period because there is an
increase in nuclear charge, but the bonding electrons are always shielded by the same inner electrons.

Question 7

trend in melting and boiling point

Answer 7

generally increase from the first to the fourth element, followed by a large decrease to the fifth element and a small general decrease to the eighth element. This is because the bonding changes from metallic to giant covalent to simple molecular covalent.

Question 8

oxidation

Answer 8

loss of electrons

Question 9

reduction

Answer 9

gain of electrons

Question 10

oxidising agent

Answer 10

is a species that accepts electrons; it becomes
reduced itself in the process

Question 11

reducing agent

Answer 11

species that donates electrons; it becomes
oxidised itself in the process.

Question 12

oxidised

Answer 12

if oxidation number increases

Question 13

reduced

Answer 13

reduction number decreases

Question 14

group 1 metals with water

Answer 14

react vigorously with cold water to form the
hydroxide and hydrogen.

Question 15

group 2 metals with water

Answer 15

react less vigorously, in fact, magnesium reacts very slowly, while calcium produces a steady stream of bubbles and a
white precipitate of calcium hydroxide. Again, the hydroxide and hydrogen are formed

Question 16

trend in reactivity

Answer 16

increases as you go down a group because when the s-block metals react they lose electrons to form positive ions. Since
ionisation energies decrease down a group, the energy needed to form positive ions decreases.

Question 17

compare group 1 and 2 metals

Answer 17

Group 1 metals are more reactive than Group 2 metals because
they lose only one electron while Group 2 metals lose two2

Question 18

group 1 and 2 reacting with oxygen

Answer 18

All Group 1 and Group 2 metals burn to form solid white oxides.

Question 19

group 1 oxide and barium oxide reacting

Answer 19

Group 1 oxides and barium oxide react with water to form a soluble hydroxide or alkali.

Question 20

soluble hydroxide ?

Answer 20

its an alkali

Question 21

alkali?

Answer 21

soluble hydroxide

Question 22

sodium flame test

Answer 22

orange yellow

Question 22

lithium flame test

Answer 22

red

Question 23

potassium flame test

Answer 23

lilac

Question 24

calcium flame test

Answer 24

brick red

Question 25

strontium flame test

Answer 25

crimson

Question 26

barium flame test

Answer 26

apple green

Question 27

solubility of group 1

Answer 27

soluble

Question 28

solubility of group 2

Answer 28

non-soluble

Question 29

trends for group 2 compounds

Answer 29

* All nitrates are soluble. * All carbonates are insoluble. * Hydroxides are more soluble as you go down the group.

Question 30

solubility trend for sulfates

Answer 30

become less soluble as you go down the group

Question 31

trend in thermal stability

Answer 31

increases as you go down the group

Question 32

group 7 halogens

Answer 32

As the number of electrons increases with atomic number, there is an increase in the induced dipole – induced dipole intermolecular forces holding the diatomic molecule together. Thus, the melting and boiling temperatures increase as you go down the group.

Question 33

chlorine at room temp

Answer 33

green gas

Question 34

bromine at room temp

Answer 34

red-brown liquid

Question 35

iodine at room temp

Answer 35

grey solid

Question 36

halogens react by gaining electrons

Answer 36

forms negative halide

Question 37

during reactions what do halogens do ?

Answer 37

in reactions halogens are reduced and they oxidise the other substance

Question 38

halogens down the group -- sheilding?

Answer 38

As you go down the group the outer electrons are shielded more and are further from the nucleus.

Question 39

halogens react directly with most metals to form

Answer 39

halides

Question 40

displacement reactions

Answer 40

A halogen in a higher position in the group will oxidise a halide ion from lower in the group

Question 41

how to test for halide ions

Answer 41

few drops of nitric acid to halide ions then add silver nitrate solution followed by diltute aq ammonia

Question 42

test for halide ions cl- chlorine

Answer 42

silver nitrate = white precipitates diluted nh3 = ppt dissolves

Question 43

test for halide ions bromine

Answer 43

silver nitrate = cream precipitate diluted nh3 = ppt dissolves slightly

Question 44

test for halide ions iodine

Answer 44

nitric acid = pale yellow precipitate diluted nh3 = no change

Question 45

chlorine in water treatment

Answer 45

Chlorine gas is added to drinking water to kill dangerous bacteria and viruses such as cholera and typhoid, thereby preventing the outbreak of serious diseases. It needs to be added in low concentrations (below 1 part per million) in order to be safe.

Question 46

fluoride in water treatment

Answer 46

Fluoride is added to water to reduce tooth decay, by preventing cavities. It is also said to strengthen bones, which helps prevent osteoporosis. Again, it appears to only have beneficial effects when added below 1 ppm.

Question 47

how are insoluble salts formed

Answer 47

by a precipitation reaction

Question 48

how are soluble salts formed

Answer 48

by neutralising an acid

Question 49

what occurs in precipitation reaction

Answer 49

two suitable solutions are mixed to form a soluble salt and an insoluble salt. For example, the formation of calcium carbonate