Periodic Table

Question 1

Periodic table divides elements into what

Answer 1

periods and groups

Question 2

Groups on periodic table 4 qualities

Answer 2

-vertical column of elements
-consists of 18 groups of element, numbered 1 to 18
-the groups run from top to bottom
-elements in the same group have the same number of valence electrons and thus have similar chemical properties

Question 3

Explain why elements in the same group have similar chemical properties

Answer 3

elements in the same group have the same number of valence electrons and thus have similar chemical properties

Question 4

Periods on periodic table 4 qualities

Answer 4

-Horizontal row of elements
-consists of 7 periods of elements, numbered 1 to 7
-The group run from left to right
-the number of electron shells an element has is the same as its period number

Question 5

Answer 5

-Reactivity of the elements decreases down group 17.
-Chlorine is able to displace both bromine and iodine from their halide solutions as chlorine is more reactive than bromine and iodine.
-Iodine cannot displace both chlorine and bromine from halide solutions as iodine is less reactive than chlorine and bromine.
-Bromine can displace iodine from its halide solution while not chlorine from its halide solution as bromine is more reactive than iodine but less reactive than chlorine

Question 6

Answer 6

In A, aqueous bromine is more reactive and displaces the less reactive lodine from aqueous iodide lons to form lodine solution (brown).
In B, aqueous iodine being less reactive than bromine, cannot displace bromine from aqueous bromide ions and remains as iodine solution (brown)

Question 7

Moving across period 2 from lithium to neon, the behaviour of the elements when they form compounds changes from metal to non/metal. Explain why

5 points

Answer 7

-Across the period, the number of electron shells stay the same while the nucleus gets increasingly positively charged.
-The metal elements (Li and Be) will have a higher tendency to lose their valence electrons to form a positive ion as the attractive force between the nucleus and the valence electrons are weaker.
-For non-metal elements (B to F), the higher nuclear charge will decrease the atomic radius of the atom and hence results in higher tendency for the atom to gain an electron to form a negative ion.
-These non-metal elements can also share electrons with other non-metals, forming covalent molecules.
-Neon is a noble gas and has a stable electronic configuration. Hence, it does not react with other elements.

Question 8

Astatine is in Group 17 of the periodic table. Which element will have similar chemical properties to astatine?

A carbon
B chlorine
C nitrogen
D sulfur

Answer 8

chlorine

Question 9

Element X is located in period 3 and group 2. deduce its electronic configuration

Answer 9

2, 8, 2

Question 10

what do elements in group 1, 2, 13 have in common

Answer 10

they are metals that tend to lose electrons to form positive ions

Question 11

what do elements in group 14, 15, 16, 17 have in common

Answer 11

they share electrons to form covalent bonds, elements in group 15 - 17 tend to gain electrons to form negative ions when bonded to a metal

Question 12

what elements in group 18 have in common

Answer 12

they are full valence electron shells, and do not form compounds

Question 13

what are metalloids

Answer 13

elements with the properties of both metals and non-metals

Question 14

state the trend of element metallic properties

Answer 14

-metals are grouped on the left-hand side of each period, while non-metals are grouped on the right-hand side
-across the period, there is a decrease in metallic property and an increase in non-metallic properties, resulting in a change in the properties of the elements

Question 15

Name the 7 metalloids

Answer 15

B, Si, Ge, As, Sb, Te, Po

Question 16

Explain how the metallic property change across the period (3 points)

Answer 16

-across the period, the number of protons in the nucleus increases while number of electron shells remain the same
-the increase in nuclear charge results in a stronger forces of attraction between the nucleus and valence electrons
-more energy is required to lose electrons resulting in lower tendency for the atom to lose electrons.
-thus the metallic property decreases

Question 17

describe the trend of change in metallic properties and non-metallic properties down a group

Answer 17

-going down a group, there is an increase in metallic properties and decrease in non-metallic properties
-the size of the atom increases due to an increase in the number of electron shells
-he valence electrons are further away from the nucleus
-hence there is weaker forces of attraction between the nucleus and the valence electrons
-there is a higher tendency for the atom to lose its valence electrons to form a positive ion

Question 18

what structure does Si have

Answer 18

giant covalent structure

Question 19

what structure does P, S, Cl have

Answer 19

simple molecular structure

Question 20

what structure does Na, Mg, Al have

Answer 20

giant metallic structure

Question 21

what structure does Na2O, MgO,Al2O3 have

Answer 21

giant ionic structure

Question 22

what ar alkali metals

Answer 22

group 1 metals. Group 1 elements can react water to form soluble metal hydroxide, alkalis

Question 23

state the 4 physical properties of alkali metals

Answer 23

-soft an can be cut easily
-good conductors of heat and electricity due to presence of delocalised mobile electrons
-low melting and boiling points
-low densities

Question 24

what group 1 elements can float on water

Answer 24

lithium, sodium, potassium. They are less dense than air

Question 25

Explain the melting and boiling points of elements trend down group 1

Answer 25

-down the group, the melting and boiling points of alkali metals decreases. -down he group, size of atom increases due to increase in number of electron shells -the valence electrons are further away from the positive nucleus, hence the forces of attraction between the nucleus and valence electrons are weaker -therefore, metallic bonding is weaker and less energy is needed to overcome the force of attraction.

Question 26

what is the trend between density and group 1

Answer 26

down the group, the density of alkali metals generally increases

Question 27

How can metals be prevented from reacting with air and water

Answer 27

alkali metals are highly reactive metals and are stored in oil to prevent hem from reacting with air and water.

Question 28

How do alkali metal react

Answer 28

They have 1 valence electron and react by losing 1 valence electron to achieve noble gas electronic configuration

Question 29

What are Alkali metals and why, then state the trend

Answer 29

powerful reducing agents as they lose their valence electrons easily. The reducing power of alkali metals increases down the group due to the increased reactivity

Question 30

Explain why the reactivity of group 1 elements increases down the group

Answer 30

-size of atom increases due to increases in number of electron shells -the valence electrons are further away from the nucleus hence there is weaker forces of attraction between the nucleus an the valence electrons -there is an increase in the ease of losing valence electrons

Question 31

Alkali metals react with water to form what products

Answer 31

an alkali and hydrogen gas

Question 32

lithium reaction with water

Answer 32

reacts quickly.lithium floats on water

Question 33

sodium reaction with water

Answer 33

reacts violently.sodium darts around the water surface. Reaction may be explosive

Question 34

potassium reaction with water

Answer 34

reacts very violently. Reaction is explosive

Question 35

Define halogens

Answer 35

elements in group 17 that are diatomic molecules and are reactive non-metals

Question 36

State the physical properties of halogens

Answer 36

-have low melting and boiling points -are coloured

Question 37

State the appearance of fluorine at rtp

Answer 37

pale yellow gas

Question 38

State the appearance of chlorine at rtp

Answer 38

yellow green gas

Question 39

State the appearance of bromine at rtp

Answer 39

red-brown liquid

Question 40

State the appearance of iodine at rtp

Answer 40

purple-black solid

Question 41

State the appearance of astatine at rtp

Answer 41

black solid

Question 42

state the 2 trends of halogen physical properties down the group

Answer 42

-melting point increases -colour intensity increases

Question 43

Explain why the melting and boiling points increases down group 17

Answer 43

-size of molecule increases resulting in stronger intermolecular forces of attraction -thus more energy is needed to overcome the stronger forces of attraction

Question 44

how do halogens react

Answer 44

they have 7 valence electrons and have a tendency to gain 1 electron to achieve noble gas electronic configuration

Question 45

What are halogens, what do they react with and what is the trend

Answer 45

oxidising agents in chemical reactions. They react with most metals to form halides (salt). The oxidising power of halogens decrease down the group as the reactivity decreases

Question 46

Explain why the reactivity of halogens decrease down the group

Answer 46

-size of atom increases due to the increase in number of electron shells -forces of attraction between the positive nucleus and the valence electrons are weaker, making it harder for the nucleus to attract one more electron

Question 46

Name 4 halide ions

Answer 46

F-, Cl-, Br-, I-

Question 47

How do displacement reaction happen (3 points)

Answer 47

-halogens undergo displacement reactions with halide solution -the more reactive halogen has a higher tendency to gain electrons and form negative ions compared to a less reactive halogen. -Thus, a more reactive halogen will displace a less reactive halogen from its compound (halide)

Question 48

state the observation and explanation for the reaction between chlorine and sodium bromide

Answer 48

-solution changes from colourless to orange-brown -chlorine is more reactive than bromine, hence chlorine displaces bromine from sodium bromide solution

Question 49

are displacement reactions involving halogens redox reactions?

Answer 49

YES

Question 50

what are noble gases/inert gases

Answer 50

elements in group 18

Question 51

state the 5 physical properties of noble gases

Answer 51

-monoatomic non-metals -colourless gases at room temperature -low melting and boiling points -insoluble in water -unreactive

Question 52

explain why noble gases are unreactive

Answer 52

they have a fully filled valence electrons shell thus they do not lose, gain or share electrons and hence rarely react to form compounds

Question 53

what are noble gases used for

Answer 53

to provide an inert atmosphere

Question 54

use of helium

Answer 54

used in balloons

Question 55

use of argon/neon

Answer 55

Used to fill tungsten bulbs to provide an inert atmosphere hat prevents oxidation of the filament

Question 56

use of argon

Answer 56

used in manufacturing of steel

Question 57

state the 5 physical properties of transition metals

Answer 57

-high melting and boiling points -high densities -has variable oxidation states -forms coloured compounds -transition metals and their compounds are good catalysts for many reactions, both in the laboratory and in the industry

Question 58

state the colour of CrCl3

Answer 58

green

Question 59

state the colour of K2Cr2O7

Answer 59

orange

Question 60

state the colour of FeCl2

Answer 60

pale green

Question 61

state the colour of FeCl3

Answer 61

yellow

Question 62

state the colour of MnO2

Answer 62

brown-black

Question 63

state the colour of KMnO4

Answer 63

purple

Question 64

state the colour of Cu2O

Answer 64

red

Question 65

state the colour of CuO

Answer 65

black

Question 66

Are the colours of hydrated and anhydrous compounds the same

Answer 66

may be different

Question 67

what is the use for iron

Answer 67

For Haber process for the manufacture of ammonia

Question 68

what is the use of nickel

Answer 68

manufacture of margarine from vegetable oil

Question 69

what is the use of manganese (IV) oxide

Answer 69

decomposition of hydrogen peroxide

Question 70

define catalyst

Answer 70

a catalyst is a substance that increases the rate of a chemical reaction and remains chemically unchanged at the end of the reaction