C3.1 The periodic table

Question 1

How did Newlands and Mendeleev order the elements?

Answer 1

In order of their atomic weights

Question 2

Why is it called ‘the periodic table’?

Answer 2

Because similar properties occur at regular intervals

Question 3

What did Mendeleev do to overcome some of the problems?

Answer 3

He left gaps for elements that he thought hadn’t been discovered

Question 4

How was the early periodic table first arranged?

Answer 4

In order of atomic numbers

Question 5

How are the elements in the modern periodic table arranged?

Answer 5

In terms of their electronic structures

Question 6

Give 4 properties of Group 1 elements

Answer 6

• Low density
• React w/ water forming hydrogen
• Form hydroxides that dissolve in water to give alkaline solutions
• React w/ non-metals—>ionic compounds (+1)

Question 7

A non-metal reacts with a Group 1 element. Describe the compound and what happens to it when it dissolves in water

Answer 7

• A white, solid. ionic compound

- Forms a colourless solution

Question 8

Which Group 1 element is the most reactive and has the lowest boiling and melting point? The one at the top or the bottom?

Answer 8

The bottom; Francium

Question 9

Describe the reactivity and boiling and melting points of Lithium, relative to Group 1

Answer 9

• Least reactive

- Highest melting and boiling points

Question 10

Compare the transition elements with the elements in Group 1 (3 marks)

Answer 10

Transition elements:

• Have higher melting points, bar Mercury
• Are stronger and harder
• Less reactive (not as vigorous with water or oxygen)

Question 11

Do most of the ions formed from the transition elements have the same charge?

Answer 11

No, many transition elements form ions with different charges

Question 12

Are many transition elements good catalysts and are the compounds they form white?

Answer 12

Many transition elements ARE good catalysts and many form COLOURED compounds

Question 13

What pattern do you see in the properties as you move down Group 7?

Answer 13

• The less reactive the element

- Higher boiling and melting point

Question 14

A more reactive halogen can displace…

Answer 14

…a less reactive halogen from an aqueous solution of its salt

Question 15

How can the trends in reactivity within groups be explained? (2 marks)

Answer 15

The higher the energy level:

• The easier it is to lose electrons
• The harder it is to gain electrons