Periodic Table

Question 1

What are the properties of group O elements?

Answer 1

• Unreactive
• do not easily form molecules
• boiling points increase going down the group

Question 2

What are the group 7 element called and when are their properties?

Answer 2

• halogens
• non metals
• all molecules (pairs of atoms?)
• further down group, reactivity decreases
• more reactive halogen can displace a less reactive halogen from an aqueous solution of its salt

Question 3

Why does the melting point of group 7 elements increase going down the group?

Answer 3

• molecules increase in size going down the group as there are more shells
• so the intermolecular forces increase which are weak

Question 4

How did Mendeleev create his periodic table in 1869?

Answer 4

• ordered elements in atomic weight
• then adjusted the order of some elements so elements with similar properties were in the same period
• left gaps for undiscovered elements