C9 The Periodic Table

Question 1

How is the periodic table arranged?

Answer 1

Elements are arranged on the periodic table in order of increasing atomic number (proton number).

Question 2

What are periods?

Answer 2

Periods are the horizontal rows that show the number of shells of electrons an atom has and are numbered from 1-7.

Question 3

What are groups?

Answer 3

These are the vertical columns that show how many outer electrons (valency electrons) each atom has and are numbered from 1-7 with a final group called Group 0 instead of group 8 -noble gases.

Question 4

What does valency tell you?

Answer 4

Valency tells you how many bonds an atom can make with another atom or how many electrons its atoms lose, gain or share, to form a compound.

Question 5

How does the group number help determine the charge that metal and non-metal ions form?

Answer 5

For metals, the group number corresponds to the number of electrons it will lose to achieve a full outer shell and the charge of the metal ion.
-Metals on left side.
For non-metals, in group 6 and 7, they will gain 1 and 2 electrons respectively to gain a full outer shell.
-Non-metals in group 7 gain 1 electron to form ions with a 1- charge.
-Non-metals in group 6 gain 2 electrons to form ions with a 2- charge.

Question 6

How does the metallic character of elements change as you move across a period and down a group?

Answer 6

The metallic character of elements decreases as you move across a period (left to right) and it increases as you move down a group.

Question 7

Why does this trend occur? (trend of metallic character)

Answer 7

This trend occurs due to atoms more readily accepting electrons to fill their valence shells rather than losing them to have the previous, already full, electron shell as their outer shell.

Question 8

What lies in between the metals and the non-metals?

Answer 8

In between them are elements referred to as metalloids which display some properties of both.

Question 9

What is the electronic configuration?

Answer 9

The electronic configuration is the arrangement of electrons into shells for an atom.

Question 10

What is the link between the electronic configuration of elements and their position on the periodic table?

Answer 10

The number of notations in the electronic configuration will show the number of occupied shells of electrons the atom has, showing the period.
And the last notation shows the number of outer electrons the atom has, showing the group number.

Question 11

What does the group number show?

Answer 11

The group number shows the number of electrons in the outer shell, so all elements in the same group have the same number of outer shells.

Question 12

How do metals become ions?

Answer 12

Metals become positive ions by losing electrons.

Question 13

How do non-metals become ions?

Answer 13

Non-metals become negative ions by gaining electrons.

Question 14

What are some metallic characters/properties?

Answer 14

Metallic properties:
-Malleable
-Conductor of heat and electricity
-Shiny
-High melting and boiling point

Question 15

What is the group 1?

Answer 15

Group 1 are metals that are also called the alkali metals as they form alkaline solutions with high pH values when reacted with water. -first column.

Question 16

What are the first three members of group 1?

Answer 16

-Lithium
-Sodium
-Potassium
These tell us enough about the patterns or trends for us to make predictions of the rest of the group.

Question 17

Why do group 1 metals react in a similar way?

Answer 17

They react in a similar way as they all have one outer electron.

Question 18

What are the physical properties of the Group 1 metals?

Answer 18

The group 1 metals:
-Shiny silvery surfaces when freshly cut.
-Conduct heat and electricity.
-Soft and easy to cut, getting even soften and denser as you move down the Group (sodium and potassium do not follow the trend in density).
-All have low melting points and low densities compared to other metals, and the melting point decreases as you move down the Group.

Question 19

What happens to the melting point as you go down the group 1?

Answer 19

The melting point decreases down group 1.

Question 20

What happens to the density as you go down the group 1?

Answer 20

The density increases going down the group.

Question 21

How does group 1 react with water?

Answer 21

All the metals form a metal hydroxide and hydrogen.
Group 1 metal + water => metal hydroxide + hydrogen

Question 22

How does lithium react with water?

Answer 22

Lithium floats and reacts gently with water.
Bubbles of hydrogen gas.
Lithium + water => lithium hydroxide + hydrogen

Question 23

How does sodium react with water?

Answer 23

Bubbles of hydrogen gas produced. The heat of this causes it to melt into a shiny ball that dashes around surface. Floats on water because it is less dense. White trail of sodium hydroxide produced which dissolves in the water producing a highly alkaline solution.
Sodium + water => sodium hydroxide + hydrogen

Question 24

How does potassium react with water?

Answer 24

Reacts very vigorously.
Bubbles of gas, the energy release of this causes it to melt into a shiny ball that dashes around the surface.
Enough heat is produced so it burns with a lilac - coloured flame.
Potassium + water => potassium hydroxide + hydrogen

Question 25

How does reactivity change as you go down group 1?

Answer 25

As you go down group 1, the metals get more reactive.
-Rubidium, Caesium and Francium will react more vigorously with air and water.

Question 26

What are the group 7 elements?

Answer 26

The group 7 elements are the halogens. They are non-metals that are very poisonous and include iodine, chlorine, bromine…

Question 27

What are halogens? - molecules?

Answer 27

Halogens are diatomic meaning they form molecules of two atoms. I2, Cl2, Br2…

Question 28

How many electrons do halogens have in their outer shell?

Answer 28

Halogens have 7 electrons in their outer shell. They will need to gain an electron to get a full outer shell.

Question 29

What are the physical properties of the halogens? And how do they change?

Answer 29

Physical properties of halogens change down the group (at room temp)
-Darker in colour.
-Melting and boiling points increase.
-Density increases.

Question 30

How does reactivity change down group 7?

Answer 30

As you go down group 7, the reactivity decreases.

Question 31

What type of atoms do halogens form?

Answer 31

Halogens form halide ions by gaining one more electron to complete their outer shells.

Question 32

What does halide mean?

Answer 32

Halide refers to the compounds formed when a halogen combines with another atom, such as a metal.

Question 33

How does the physical state of the halogens change as you go down the group?

Answer 33

Chlorine is a pale yellow gas, bromine is a red-brown liquid and iodine is a grey-black solid; This demonstrates that the density of the halogens increase as you go down the group.

Question 34

How does the number of shells of electrons (notations) change as you go down group 7?

Answer 34

As you go down group 7, the number of shells of electrons increases. This means that the outer electrons are further away from the nucleus so there are weaker electrostatic forces of attraction which make it harder to attract an incoming electron to complete the full outer shell.

Question 35

How does melting point of halogens change as you go down the group?

Answer 35

As you go down group 7, the melting and boiling points increase.
Astatine is at the bottom of group 7 and thus has the highest melting point.

Question 36

How does density of halogens change as you go down the group?

Answer 36

As you go down group 7, the density increases.
Fluorine is at top and is a gas.
Astatine is at bottom and is a solid.

Question 37

How does the colour of halogens change as you go down the group?

Answer 37

As you go down group 7, the colour of the halogen’s becomes darker.
Fluorine is at top and is very light.
Astatine is at bottom and is black.

Question 38

What is a halogen displacement reaction?

Answer 38

A halogen displacement reaction occurs when a more reactive halogen displaces a less reactive halogen form an aqueous solution of its halide.

Question 39

What is group 0?

Answer 39

Group 0 are the noble gases. They are non-metals.
They are all monatomic meaning they exist as He, Ne, Ar…
Last column on right hand side of periodic table.

Question 40

What are the melting points like for noble gases?

Answer 40

Nobles gases have very low melting and boiling points.

Question 41

What are noble gases in terms of atoms?

Answer 41

Noble gases are all monoatomic, colourless gases. - Exist as single atoms such as He, Ne, Ar…

Question 42

Why are noble gases so unreactive and inert?

Answer 42

Noble gases are unreactive and inert because they have full outer shells meaning a very stable electronic configuration. They do not easily lose or gain electrons.

Question 43

What does inert mean?

Answer 43

Inert is a substance that does not react chemically with any other substance.

Question 44

Why do noble gases have low melting points?

Answer 44

They have low melting points because of the weak intermolecular forces of attraction that do not require a lot of energy to break. They are monoatomic and thus have very weak interatomic/intermolecular attractions.

Question 45

How can noble gases be used? Helium for filling balloons.

Answer 45

Helium is used in balloons because it is less dense than air so the balloons float and extremely unreactive whereas hydrogen is also light but reactive with air. Helium is also non flammable.

Question 46

How can noble gases be used? Neon in signs.

Answer 46

Neon is used in advertising signs because it glows red when a high voltage is passed through.

Question 47

How are noble gases used? Argon in lamps.

Answer 47

Argon/krypton/xenon can be used for filament lamps because they stop the oxygen in the light bulbs from corroding the hot tungsten filament.

Question 48

What are the uses of the noble gases? Argon in welding.

Answer 48

Argon acts as a shielding gas in welding as it is denser than air so keeps the air off of the metal and inert so metal won”t oxidise.

Question 49

How many electrons do noble gases have in their outer shell?

Answer 49

All noble gases except for helium have 8 electrons in their outer shell.
Helium only has 2.

Question 50

Where are the transition elements found?

Answer 50

The transition elements are found in the central part of the periodic table and are metals.

Question 51

What are the physical properties of the transition metals?

Answer 51

The transition metals are very hard and strong metals.
They conduct heat and electricity.
The transition elements form coloured compounds.

Question 52

What are the melting points of transition elements?

Answer 52

Transition elements have high melting points.

Question 53

What is the density of transition elements?

Answer 53

The transition elements have high density.

Question 54

What do transition metals often have?

Answer 54

Transition metals often have more than one oxidation state, such as iron readily forming compounds of both Fe2+ and Fe3+.

Question 55

What are transition metals used for?

Answer 55

Transition metals can be used as catalysts to improve the rest or reaction in industrial processes.

Question 56

What is a catalyst?

Answer 56

A catalyst is a substance that increases the rate of reaction without being used up.