Chapter 9

Question 1

Describe the Periodic Table

Answer 1

a method of classifying elements and its use to predict properties of elements

Question 2

Describe the change from metallic to non- metallic character across a period

Answer 2

The metallic character change across a period decreases and subsequently, the non-metallic character change across a period increases.

Question 3

Describe and explain the relationship between group number, number of outer-shell electrons and metallic/non-metallic character

Answer 3

The group number is the same as the number of electrons in the outer shell of an atom of that group. In general, metals have fewer electrons in their outer shell while non-metals have more electrons. The period number is the number of shells.

Question 4

Describe lithium, sodium and potassium in Group I

Answer 4

a collection of relatively soft metals that can have their surfaces tarnished when cut. When going down the group, the reactivity and density increases and the melting point decreases. Their reactivity with water also increases.

Question 5

Describe the halogens, chlorine, bromine and iodine in Group VII

Answer 5

a collection of diatomic non-metals. When going down the group, the colour increased in darkness and their density increases. Th reactivity decreases. When a more reactive element comes into contact with a less reactive element in a compound, a displacement reaction takes place. Those compounds formed with halogens are halides. Example: chlorine + sodium bromide → sodium chloride + bromine however sodium chloride + iodide → no reaction.

Question 6

Identify trends in groups, given information about the elements concerned

Answer 6

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Question 7

Describe the transition elements

Answer 7

a collection of metals having high densities, high melting points and forming coloured compounds, and which, as elements and compounds, often act as catalysts and have varying oxidation states

Question 8

Describe the noble gases, in Group VIII or 0

Answer 8

unreactive, monoatomic gases. Only being boring due to the fact that they have a full outer shell.

Question 9

State the uses of the noble gases

Answer 9

Neon is used in advertising when electricity is passed through it. Party balloons are filled with helium as it is less dense than air (hydrogen is not used as it is highly flammable). It is also used to prevent reactions from taking place. Lamps can be filled with argon, which stops the very thin metal filament from reacting with air. Without argon, the filament would react with oxygen from the atmosphere as it heated up, causing it to burn.