Topic 1 - Atomic structure and the periodic table (4)

Question 1

GROUP 1 ELEMENTS:
What are the group 1 elements also known as?

Answer 1

alkali metals

Question 2

GROUP 1 ELEMENTS:
How many electrons are in their outer shells, why is this important?

Answer 2

they all have one electron in their outer shell which makes them very reactive and gives them similar properties

Question 3

GROUP 1 ELEMENTS:
Name 3 physical properties of alkali metals?

Answer 3

• they are soft
• they have low densities
• low melting and boiling points

Question 4

GROUP 1 ELEMENTS:
What are 3 trends as you go down group 1?

Answer 4

• Increasing reactivity
• Decreasing melting and boiling points
• Higher relative atomic mass

Question 5

GROUP 1 ELEMENTS:
What happens to the reactivity of elements as you move down group 1? Why?

Answer 5

• reactivity increases
• the outer electron is more easily lost as the electrostatic attraction between the nucleus and the electron decreases, beacause the electron is further away from the nucleus the further down the group you go (as their are more shells)

Question 6

GROUP 1 ELEMENTS:
What happens to melting and boiling points as you go down group 1?

Answer 6

• lower melting and boiling points

Question 7

GROUP 1 ELEMENTS:
What happens to the atomic mass of elements as you move down group 1?

Answer 7

• higher relative atomic mass

Question 8

GROUP 1 ELEMENTS:
What do alkali metals usually react with and form?

Answer 8

they react with non-metals to form ionic compunds

Question 9

GROUP 1 ELEMENTS:
What ions do alkali metals form?Why?

Answer 9

• they don’t need much energy to lose their one outer electron to form a full outer shell, so they readily form 1+ ions

Question 10

GROUP 1 ELEMENTS:
What are the ionic compunds formed with alkali metals like?

Answer 10

• generally white solids thet dissolve in water to form colourless solutions

Question 11

GROUP 1 ELEMENTS:
What happens when alkali metals react with water?

Answer 11

• the react vigourously to produce hydrogen gas and metal hydroxides (compounds that dissolve in water to produce alkaline solutions)

Question 12

GROUP 1 ELEMENTS:
Which alkali metals react more vigourously with water?

Answer 12

• the more reactive (lower down in the group) an alkali metal is, the more violent the reaction

Question 13

GROUP 1 ELEMENTS:
When group 1 metals react with water, which ones give out the msot energy?

Answer 13

The amount of energy given out by the reaction increases down the group - the reaction with potassium releases enough energy to ignite hydrogen

Question 14

GROUP 1 ELEMENTS:
How do different alkali metals react with chlorine?

Answer 14

• they react vigourously when heated in chlorine gas to form white metal chloride salts
• as you go down the group, reactivity increases so the reaction with chlorine gets more vigourous

Question 15

GROUP 1 ELEMENTS:
Why may group 1 metals tarnish in the air?

Answer 15

the metal reacts with oxygen in the air to form a dull metal oxide layer

Question 16

GROUP 1 ELEMENTS:
What happens when alklai metals react with oxygen?

Answer 16

• they react with oxygen to form a metal oxide
• different types of oxide will form depending on the group 1 metal

Question 17

GROUP 1 ELEMENTS:
How does the reactivity of alkali metals compare to that of transition metals?

Answer 17

• group 1 metals are much more reactive than transition metals, for example, they react much more vigourously with water, oxygen or group 7 elements

Question 18

GROUP 1 ELEMENTS:
Compare the key physical properties of group 1 and transition metals?

Answer 18

• group 1 metals are much less dense, strong and hard than transition metals and have much lower melting points e.g. manganese melts at 2000C, sodium melts at 98C

Question 19

GROUP 7 ELEMENTS:
What are the group 7 elemants also known as?

Answer 19

Halogens

Question 20

GROUP 7 ELEMENTS:
What do all of the halogens have in common?

Answer 20

they are all non-metals with coloured vapours

Question 21

GROUP 7 ELEMENTS:
What are the basic properties of theses 4 halogens?
- fluorine
- chlorine
- bromine
- iodine

Answer 21

• fluorine is a very reactive, poisonous yellow gas
• chlorine is a fairly reactive, poisonous dense green gas
• bromine is a dense, poisonous, red-brown volatile liquid
• iodine is a dark grey crystalline solid or a purple vapour

Question 22

GROUP 7 ELEMENTS:
How do all halogens exist?

Answer 22

as molecules which are pairs of atoms

Question 23

GROUP 7 ELEMENTS:
What are the 3 main trends as you go down group 7 (the halogens)?

Answer 23

• halogens become less reactive
• halogens have higher melting and boiling points
• halogens have higher relative atomic masses

Question 24

GROUP 7 ELEMENTS:
Why do all halogens react in similar ways?

Answer 24

they all have 7 electrons in their outer shell

Question 25

GROUP 7 ELEMENTS: How can halogens form molecular compounds?

Answer 25

halogen atoms can share electrons via covalent bonding with other non-metals to get a full outer shell.

Question 26

GROUP 7 ELEMENTS: Give the chemical symbols of 4 compunds with covalent bonds and halogens?

Answer 26

HCl PCl 5 HF CCl 4

Question 27

GROUP 7 ELEMENTS: What is the structure of the compounds that form when halogens react with other non-metals?

Answer 27

simple molecular structures

Question 28

GROUP 7 ELEMENTS: What happens when halogens form ionic bonds?

Answer 28

- the halogens form 1- ions called halides when they bond with metals - compunds that form have ionic structures

Question 29

GROUP 7 ELEMENTS: How can displacement reactions happen between halogens?

Answer 29

- more reactive halogens will displace less reactive ones - a displacement reaction can occur between a more reactive halogen and the salt of a less reactive one

Question 30

GROUP 7 ELEMENTS: Give an example of how halogens can displace each other?

Answer 30

Chlorine can displace bromine and iodine from an aqueous solution of its salt (a bromide or iodide). Bromine will also displace iodine because of the trend in reactivity