Chapter 13: The Periodic Table

Question 1

What is the periodic table?

Answer 1

A table of elements arranged in order of increasing proton number (atomic number) to show the similarities of the chemical elements with related electronic configurations.

Question 2

What are groups?

Answer 2

Vertical columns of the Periodic Table containing elements with similar chemical properties; the atoms of elements in the same group have the same number of electrons in their outer energy levels.

Question 3

What are periods?

Answer 3

A horizontal row of the Periodic Table

Question 4

What are metalloids? (2)

Answer 4

-An element that shows some of the properties of the metals and some of the non-metals.
eg boron and silicon
-They are close to the line that separates metals and nonmetals.

Question 5

Properties of metalloids? (2)

Answer 5

-They often look like metals but are brittle like non-metals.
-They are neither conductors nor insulators but make excellent semiconductors.

Question 6

What are the main group elements? (2)

Answer 6

-The elements in the other groups of the periodic table, excluding the transition elements.
-These vertical groups show most clearly how elements within the same group have similar chemical and physical properties.

Question 7

What are transitional elements? (3)

Answer 7

Between the main group elements (G2 and G3) lies a block of metals known as transitional elements.
-They form the central region of the periodic table.
-They are hard, strong, dense metals which form compounds that are often coloured.

Question 8

What are alkali metals?

Answer 8

Elements in Group 1 of the Periodic Table; They are the most active group of metals.

Question 9

Why is hydrogen not placed in a group in the periodic table? (2)

Answer 9

-It is the smallest atom of all it’s properties are distinctive ad unique.
-It does not fit well in the trends of any group.

Question 10

Properties of hydrogen

Answer 10

-Gas at room temperature.
-Non-metal, forms diatomic molecules.
-Atom has one electron in its outer shell.
-Atom can form either a positive or a negative ion: can gain one electron or lose its only electron.

Question 11

What is a periodic properly?

Answer 11

A property of the elements that shows a repeating pattern when plotted against proton number (z).

Question 12

Properties of groups (2)

Answer 12

-Elements in the same group have the same number of electrons in their outer shell.
-For main group elements, the number of the group is the number of electrons in the outer shell.

Question 13

Properties of the periodic table?

Answer 13

Periodic Number shows how many shells of the electrons the atom has.

Question 14

What does the outer electrons of an atom show?

Answer 14

It is mainly responsible for the chemical properties of any element and therefore elements in the same group will have similar.

Question 15

What are noble gases?

Answer 15

They have the most stable arrangements and therefore they are unreactive. They are elements in Group VIII- a group of stable very unreactive gases.

Question 16

What is the relationship between group number and ionic charge?

Answer 16

-The metal ions have a positive charge and they are the same as the group number.
-They have to lose their outermost electrons to achieve the closest noble gas configuration. (to form an ion).

Question 17

And for non-metals?

Answer 17

-The negative charge on the ion is 8 minus the group number.
-These elements have to gain electrons to reach the closest noble gas configuration (to form an ion).

Question 18

Elements in the middle of the periodic table?

Answer 18

They usually from covalent bonds rather than ionic compounds.

Question 19

Precaution due to the reactivity of group one metals-

Answer 19

-Due to their reactivity they are stored under oil to prevent them from reacting with the air (water and oxygen).

Question 20

Observations when cut with a knife (Group One)

Answer 20

When freshly cut with a knife all the metals have light grey, silvery surfaces which quickly tarnish and become dull.

Question 21

Why are alkali metals known as alkali metals?

Answer 21

Because they react vigorously with water to produce hydrogen and an alkaline solution.

Question 22

Francium?

Answer 22

-Francium is highly radioactive and very rare because it decays with half-life of 5 minutes. —-The amount of francium in any sample is halved in 5 minutes.
-Only 30g of francium on Earth.

Question 23

What are halogens?

Answer 23

Elements of group VII of the periodic table- generally the most reactive of group of non metals.

Question 24

What are halides?

Answer 24

Compounds formed between an element and a halogen eg sodium iodide.

Question 25

Properties of chlorine (4)

Answer 25

-Dense, pale green -Smelly and poisonous -Occurs as chlorides the sea. -Relative atomic mass 35.5

Question 26

Properties of bromine (4)

Answer 26

-Deep red liquid with red, brown vapour. -Smelly and poisonous -Occurs as bromides, especially magnesium bromide in the sea. -Relative atomic mass 80.

Question 27

Properties of Iodine (5)

Answer 27

-Grey solid with purple vapour -smelly and poisonous -occurs as iodides and iodates -in some rocks and in seaweed -Relative atomic mass 127

Question 28

Properties of halogens (7)

Answer 28

-They are all poisonous and have a similar strong smell -They are all nonmetals -all form diatomic molecules -They have the valency of 1 and form compounds with similar formulas (ending with ide). -Their compounds with hydrogen are usually strong acids when dissolved in water eg hydrochloric acid, hydrobromic acid, and hydroiodic acid. -They produce a series of compounds with other elements eg chlorides, bromides and iodides. These are known as halides. -The halogens themselves can react directly with metals to form metal halides (or salts). -They all form negative ions carrying a single charge eg chloride ions (Cl-), bromide ions (Br-) and iodide ions (I).

Question 29

Reactions of Halogens (2)

Answer 29

-Dutch metal foil can alloy of copper and zinc, will burst into flames when placed in a gas jar full of chlorine. -When chlorine passed over heated aluminium the metal glows white and forms aluminium chloride.

Question 30

Aluminium with bromine and iodine (2)

Answer 30

-The reaction between a dry mixture of powdered aluminium and iodine can be triggered by adding just a few drops of water. -The reaction is highly exothermic and some of the iodine is given off as purple fumes before it has a chance to react. Hydrogen (burns in) + Chlorine --> Hydrogen Chloride (Carried out in a different way can e explosives.

Question 31

What happens between chlorine and water? (2)

Answer 31

-Chlorine dissolves in water to form an acidic solution. -This mixture is called chlorine water and contains 2 acids Cl2 + H2O --> HCl (hydrochloric acid) + HClO(hypochlorous acid).

Question 32

What is the halogen displacement reaction?

Answer 32

Reactions in which the more reactive halogen displaces a less reactive halogen from a solution of its salt.

Question 33

What are noble gases?

Answer 33

Elements in Group VIII - a group of stable, very unreactive gases.

Question 34

Uses of Noble gases (4)

Answer 34

-Helium is used in airships and balloons because it is both light and unreactive. -Argon is sued to fill incandescent light bulbs because it will not react with eh filament even at high temperatures. -Noble gases are used in neon lights where the brightly coloured advertising lights work when an electric discharge takes place in a tube containing small amounts of a noble gas. -Different gases give a different colour.

Question 35

Properties of a Noble gas (3)

Answer 35

-The electron electronic configuration of the atoms of the noble gases is energetically stable. -This means that they do not react readily with other atoms. -In many situations where atoms of other elements bond or react chemically they are trying to achieve the energetically stable arrangement of electrons found in the noble gas.

Question 36

What is an oxidation number?

Answer 36

A number given to show whether an element has been oxidised or reduced the oxidation number of a simple ion is simply the charge on the ion.