C2-Periodic Table

Question 1

In the periodic table how do elements with similar properties occur

Answer 1

Elements with similar properties occur at regular intervals in the periodic table

Question 2

Why do all elements in a group have similar propeties

Answer 2

All elements in groups have similar properties because they all react similarly , this is because they all have the same amount of electrons in their outer shell

Question 3

How was the early periodic table developed

Answer 3

The early periodic table was first developed by Johann doberiener who discovered that elements with similar properties often occurred in three. He called these triads.

The periodic table was then further developed by John Newlands who arranged the particles in terms of atomic weight and noticed that every 8th element reacted similarly. He called this the law of octaves but many scientist did not take this seriously because some of the properties of every 8th one didnt fit into his theory

Question 4

How was the modern periodic table developed by Dimitri Mendeleev

Answer 4

Dimitri Mendeleev first put all the atoms in order of atomic weight but then changed the elements around if they fitted into the patterns of other groups. He also then left gaps for undiscovered elements as he knew not all of them had been discovered.He was able to predict the properties of undiscovered elements though due to the group they were in.

Once these elements were discovered and they matched mendeleevs predictions, many scientists started to trust in medeleev’s PT

Question 5

What are the differences between the modern Periodic table and Mendeleev’s periodic table

Answer 5

• The modern periodic table is arranged in terms to atomic number whereas Mendeleev’s was arranged in terms of atomic weight. The reason for this is because atomic number is the number of protons and protons had not been discovered then so Mendeleev did not have access to these numbers. The problem with using atomic weight is that the order can appear wrong due to the presence of Isotopes
• Group 7 elements also hadnt been discovered when Mendeleev developed his periodic table

Question 6

What are group 1 metals called and how many electrons do they have in their outer shell

Answer 6

Group 1 metals are called alkali metals and tthey have one electron in their outer shell

They are not very dense and have relatively low melting points and they are soft

They form +1 ions when they react

Question 7

How do group 1 metals react with water

Answer 7

Group 1 metals react vigourusly with water

-They react more vigourusly the further you go down the group because the electrons are further away from the nucleus which means the attraction between the electrons and the nucleus decreases

Question 8

What is the equation for when group 1 metals react with Oxygen

Answer 8

4Li +O2—->2Li20

Can be used for any group one metal

Two atoms of a group one metal give away an electron to give oxygen a full outer shell. They become negative ions

Question 9

How do group 1 metals react with chlorine

Answer 9

Group 1 metals react vigourusly with Chlorine

2Li + Cl2 —>2LiCl
Balanced

Can be written for any group 1 metal

Question 10

How do group one metals react with water

Answer 10

Group one metals react more vigorusly with water as you go down the group

Overall the reaction that can be used for group one metals and water is
Lithium + water —-> Lithium hydroxide + hydrogen

The water, if universal indicator is added turns purple as lithium hydroxide is an alkali

Question 11

Why do group 1 metals get more reactive the further you go down the group

Answer 11

Moving down the group the outer electron is less attracted to the positively charged nucleus. This means it is easier to lose.

This is because there is a greater difference in distance between the nucleus and the outer shell

The outer electron is sheilded from the nucleus by the internal structure

Question 12

What are the properties of group 7 elements

Answer 12

Group 7 elements are called the halogens

They each have 7 outer electrons in their outer energy level

Their melting and boiling points increase as you go down the group

Question 13

How do group 7 elements react with other elements in group 7

Answer 13

Group 7 elements share an electron and form a covalent bond with other group 7 elements to form a molecule (e.g F2)

Question 14

How do group 7 elements react with metals

Answer 14

Group 7 elements form ionic compounds with metals. They gain one electron to gain a full outer shell and form a -1 ion

Question 15

How do group 7 elements react with non metals

Answer 15

Group 7 elements form covalent compounds with other non metals and share one outer electron

Question 16

How does reactivity change as you go down group 7

Answer 16

The elements at the top of group 7 are more reactive than the ones at the bottom

This is because it is easier for them to gain an electron

This is because for the elements at the bottom of group 7 there is not a strong attraction between the nucleus and the outer energy level because of the distance between them and because at the bottom the outer energy levels are being sheilded by the internal structure. This makes it hard for them to attract the outer electron

Question 17

What happens with more and less reactive halogens in aqueous solutions of salts

Answer 17

A more reactive halogen will displace a less reactive halogen from an aqueous solution of its salt

Sodium Iodide + fluorine —-> sodium flouride + iodine

This is because the flourine is more reactive than the iodine

If an element is less reactive it will not be able to displace the element out of the solution and the reaction will not change

Question 18

What happens to the boiling, melting points and the RAM of elements moving down group 7

Answer 18

The metling and boiling points of the elements increase as you go down group 7

The RAM increases aswell going down the group

Question 19

What are the properties of group 0 elements

Answer 19

Group zero elements are called the noble gases

They are very unreactive because they have a full outer shell

The boiling points and melting points of group zero metals decrease going down the group

Question 20

What are the properties of transition metals

Answer 20

Transition metals :

• Are Hard and strong metals
• Have relatively high densities
• React less vigourusly than group 1 metals
• Have high melting points ( apart from mercury)
• They can form ions with different charges
• They form coloured compounds
• They can be used as catalysts

Question 21

What are the properties of metals

Answer 21

• Metals are strong but can be hammered into different shapes(malleable)
• Metals have high melting and boiling points
• They are good conductors of heat and electricity

Question 22

What are the properties of non metals

Answer 22

They are brittle, not great conductors of heat and electricity and not always solids at room temperature