Recall the physical and chemical properties of groups 1, 7 & 0

Question 1

What are group 1 metals known as

Answer 1

The alkali metals

Question 2

Why do alkali metals all have similar chemical properties

Answer 2

• They all have one electron in the outer shell

Question 3

What are the physical properties of alkali metals

Answer 3

• Low melting and boiling points compared to other metals
• low density - Li, Na, K float on water
• Very soft - they can be cut with a knife

Question 4

Why are group 1 metals reactive?

Answer 4

• They readily lose their one outer electron to form a +1 ion to get a stable electronic structure
• as you go down group 1 the alkali metals get more reactive
• because outer electron is easily lost because the atomic radius is larger
• therefore it’s less strongly attracted to nucleus and less energy needed to remove it

Question 5

Describe the reaction between a alkali metal and cold water

Answer 5

• Reacts vigorously
• produces metal hydroxide + hydrogen

Question 6

describe the reaction between rubidium and cesium with water

Answer 6

• react violently with watee and explode

Question 7

what is the balanced equation of sodium + water

Answer 7

2Na+2H₂O→2NaOH+H₂

Question 8

What are the group trends for group 1

Answer 8

Down the group:

• increasing atomic radius
• decreasing electronegativity
• increasing reactivity
• decreasing melting and boiling pointsincreasing atomic radius

Question 9

What would you see when lithium reacts with water

Answer 9

• When lithium is added to wafter it floats.
• It fizzes steadily and becomes smaller, until it eventually disappears.

Question 10

What is the word and symbol equation for lithium reacting with water

Answer 10

• lithium + water → lithium hydroxide + hydrogen
• 2Li(s) + 2H₂O(l) → 2LiOH(aq) + H₂(g)

Question 11

What would you see if sodium reacted with water

Answer 11

• the sodium melts to form a ball that moves around on the surface
• It fizzes rapidly
• produces hydrogen that may burn with an orange flame before the sodium disappears.

Question 12

What is the word and symbol equation of sodium reacting with water

Answer 12

• sodium + water → sodium hydroxide + hydrogen
• 2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)

Question 13

What would you see if potassium reacted with water

Answer 13

When potassium is added to water

• It melts and floats around very quickly on the surface of the water.
• The hydrogen ignites instantly.
• The metal is also set on fire, with sparks and a lilac flame.
• There is sometimes a small explosion at the end of the reaction.

Question 14

What is the word and symbol equation for potassium reacting with water

Answer 14

• potassium + water → potassium hydroxide + hydrogen
• 2K(s) + 2H₂O(l) → 2KOH(aq) + H₂(g)

Question 15

what are group 7 elements known as?

Answer 15

the halogens

Question 16

what are the elements on group 7

Answer 16

• fluorine
• chlorine
• bromine
• iodine
• astatine

Question 17

why do group 7 elements exist as diatomic molecules?

Answer 17

because they share a pair of electrons in a covalent bond giving both toms a full outer shell

Question 18

what happens as you go down group seven ?

Answer 18

• melting and boiling points increase
• reactivity decreases
• Color becomes darker
• State of change gas to liquid to solid

Question 19

at room temperature what color is

1. chlorine
2. bromine
3. iodine

Answer 19

• chlorine: fairly reactive, poisonous green gas
• bromine: poisonous brown orange liquids gives off an orange vapor at room temp
• iodine: dark grey solid purple vapor when heated

Question 20

why does reactivity decrease going down group 7

Answer 20

• gain one electron to 1- ion
• as you go down the group, less reactive as it gets harder to gain extra electron to make full outer shell when its further away form the nucleuas

Question 21

what happens when halogens react with alkali metals

Answer 21

• form salts called metal halides
• eg : sodium+ chlorine → sodium chloride | 2Na+Cl₂ → 2NaCl
• eg: potassium + bromine → potassium bromide | 2K+Br₂→ 2KBr

Question 22

what is a displacement reaction?

Answer 22

• a displacement reaction is where a more reactive element displaces a less reactive element from a compound

Question 23

describe what happens in the chlorine water and potassium bromide practical

Answer 23

• chlorine is more reactive than bromine
• if you add chlorine water to potassium bromide
• chlorine will displace the bromine and becomes potassium chloride
• the bromide ions are oxidized to bromine turning orange

Question 24

write a balanced equation for chlorine and potassium bromide displacement reaction

Answer 24

chlorine + sodium bromide → sodium chloride + bromine

Cl₂(aq) + 2NaBr(aq) → 2NaCl(aq) + Br₂(aq)

Question 25

how can displacement reactions show reactivity trends

Answer 25

* start by adding small amount of halide solution in test tube * add a few drops of a halogen solution to it and shake tube gently * color change=reaction * the halogen replaced the halide ions from salt * no color change no reaction

Question 26

explain what is happening and what is made

Answer 26

**_when chlorine water is added to:_** * potassium bromide solution-an orange solution is formed * potassium iodide solution - a brown solution is formed **_when bromine water is added to:_** * potassium iodide solution- a brown solution is formed * chlorine displaces both bromine and iodine . bromine only displaces iodine . Iodine doesn't displace either

Question 27

Florine reaction with iron wool

Answer 27

* Reacts with almost anything instantly. * dangerous

Question 28

Chlorine reaction with iron wool

Answer 28

Reacts with heated iron wool very quickly.

Question 29

Bromine reaction with iron wool

Answer 29

Has to be warmed and the iron wool heated. The reaction is faster.

Question 30

Iodine reaction with iron wool

Answer 30

Has to be heated strongly and so does the iron wool. The reaction is slow

Question 31

Why do boiling and melting points increase as you go doen group 7

Answer 31

* the molecules become larger * the **_intermolecular forces_** become stronger * more **_energy_** is needed to overcome these forces

Question 32

What is made when a halogen reacts with a non metal use chlorine and hydrogen

Answer 32

* A compound is formed * hydrogen + chlorine → hydrogen chloride * H2(g) + Cl₂(g) → 2HCl(g)

Question 33

Describe the reaction between hydrogen and Florine

Answer 33

* Explodes at room temperature and in the dark, forming hydrogen fluoride

Question 34

Describe the reaction between hydrogen and chlorine

Answer 34

Explodes with a flame or in sunlight, forming hydrogen chloride

Question 35

Describe the reaction between hydrogen and **bromine**

Answer 35

* Vigorous reaction when warmed with hydrogen, forming hydrogen bromide

Question 36

Describe the reaction between hydrogen and iodine

Answer 36

* Very slow reaction when heated strongly, forming some hydrogen iodide

Question 37

What happens when the hydrogen halides are put into water

Answer 37

The hydrogen halides are gases at room temperature. They **_dissolve**_ in water to produce _**acidic**_ _**solutions_**.

Question 38

what is group zero known as

Answer 38

* the noble gasses

Question 39

at room temperature what color are all of the gasses ?

Answer 39

colorless

Question 40

why are the noble gasses all monotonic

Answer 40

* because they're all made up of single **atoms**

Question 41

why are the noble gasses inert (unreactive)

Answer 41

* because they all have full outer shells * meaning they dont give or gain electrons easily

Question 42

why are the noble gasses non flammable

Answer 42

because they are inert

Question 43

name the group zero elements

Answer 43

* helium * neon * argon * krypton * xenon * radon

Question 44

as you go down the group what happens to the * boiling point * melting point * density

Answer 44

increase

Question 45

how to estimate the densities of group 0 elements eg use the densities of helium (0.2kg/m³) and argon (1.8kg/m²) to estimate the density of neon

Answer 45

* (0.2 + 1.8)/2=1 * neon should have a density around 1kg/m³

Question 46

why do group 0 elements react in similar ways

Answer 46

* they all have full outer electron shells