C4 - Chemical patterns

Question 1

Each element have different….

Answer 1

PROTON NUMBERS

Question 2

Arranging the elements in order of their proton numbers gives…

Answer 2

…repeating patterns in the properties of elements.

Question 3

Which three scientists were involved in coming up with ideas about the Periodic Table?

Answer 3

Dobereiner, Newlands and Mendeleev.

Question 4

What did Dobereiner research?

Answer 4

He put the list of the known elements into groups based on their chemical properties. He put these into groups of THREE, which are called ‘TRIADS’.

The MIDDLE ELEMENT of each triad had a RELATIVE ATOMIC MASS that was the AVERAGE of the other two.

Question 5

What did Newlands research?

Answer 5

He noticed that when you arranged the elements in order of relative atomic mass, every EIGHTH ELEMENT had similar properties and so he grouped them into OCTAVES.

Question 6

What is one reason as to why Dobereiner’s triads were rejected?

Answer 6

Most elements did not fit their ‘patterns’.

Question 7

What are 3 reasons as to why Newland’s Law of Octaves were criticised by the Chemical Society in 1985?

Answer 7

1. His groups contained elements that didn’t have similar properties, e.g. carbon and titanium.
2. He mixed up metals and nonmetals. e.g. oxygen & iron.
3. He didn’t leave any gaps for elements that hadn’t been discovered yet.

Question 8

What did Mendeleev research?

Answer 8

He realised that arranging the elements in order had
some elements in groups with elements with very
different properties. He left gaps for future elements and this also allowed him to predict the properties of these undiscovered elements.

He ordered the table by atomic (proton) number instead of RFM.

Question 9

Why was Mendeleev’s idea of the Periodic Table accepted and approved?

Answer 9

Mendeleev in the end was correct because the newly discovered elements fitted into the gaps he left.

Question 10

What is the VERTICAL column in a Periodic Table called?

Answer 10

GROUP

Question 11

What makes elements in each group of the PT so alike to each other?

Answer 11

They have SIMILAR PROPERTIES.

Question 12

What are the ROWS called in a Periodic Table?

Answer 12

PERIOD

Question 13

What is Group 1 known as?

Answer 13

The alkali metals

Question 14

What are the 6 metals in Group 1?

Answer 14

Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Caesium (Cs), Francium (Fr)

Question 15

When you cut alkali metals what happens to them?

Answer 15

They are shiny when freshly cut but tarnish rapidly in moist are due to the reaction with oxygen.

Question 16

As you go DOWN Group 1, the akalis:
become \_\_\_\_\_\_ REACTIVE
have a \_\_\_\_\_\_\_ DENSITY
have a \_\_\_\_\_\_\_\_ MELTING POINT
have a \_\_\_\_\_\_\_\_ BOILING POINT

Answer 16

As you go DOWN Group 1, the alkalis become:
MORE REACTIVE
have a HIGHER DENSITY
have a LOWER MELTING POINT
have a LOWER BOILING POINT

Question 17

When lithium, sodium or potassium are put in water, what happens?

Answer 17

They react very VIGOROUSLY (they move around the surface, fizzing furiously).

Question 18

What two products do Group 1 metals form when reacted with water?

Answer 18

HYDROGEN and a METAL HYDROXIDE (an alkali and turns pH blue)

Question 19

What is the word equation for the reaction of a metal with water?

Answer 19

metal + water –> metal hydroxide + hydrogen

Question 20

If M represents a metal, what is the symbol equation for the reaction of a metal with water?

Answer 20

2M (s) + 2H2O (l) –> 2MOH (aq) + H2 (g)

Question 21

When alkali metals react with chlorine, what happens?

Answer 21

They react VIGOROUSLY with chlorine.

Question 22

What does the reaction of an alkali metal with chlorine produce?

Answer 22

COLOURLESS crystalline salts, e.g. LiCl (lithium chloride), NaCl (sodium chloride), KCl (potassium chloride)

Question 23

If M represents a metal, what is the symbol equation for the reaction of a metal with chlorine?

Answer 23

2M (s) + Cl2 (g) –> 2MCl (s)

Question 24

What are the 6 main hazard symbols?

Answer 24

1. HIGHLY FLAMMABLE
2. TOXIC
3. CORROSIVE
4. HARMFUL
5. EXPLOSIVE
6. OXIDISING

Question 25

How can you test for hydrogen?

Answer 25

A lighted splint which produces a ‘squeaky pop’ as it ignites.

Question 26

Why are Group 1 metals dangerous?

Answer 26

They are flammable and their hydroxides are harmful and corrosive.

Question 27

When handling Group 1 metals, what necessary precautions should be carried out?

Answer 27

They should be kept away from water and naked flames.

Question 28

What are the Group 7 elements known as?

Answer 28

The HALOGENS

Question 29

What are the 5 elements in Group 7?

Answer 29

Fluorine (F), Chlorine (Cl), Bromine (Br) , Iodine (I) , Astatine (At)

Question 30

What are the states and colours of the 5 elements in Group 7 at room temperature and pressure?

Answer 30

Fluorine - very reactive, poisonous YELLOW GAS
Chlorine - fairly reactive, poisonous DENSE GREEN GAS
Bromine - Dense, poisonous, ORANGE VOLATILE LIQUID and forms an ORANGE GAS
Iodine - DARK GREY crystalline SOLID or a PURPLE VAPOUR

Question 31

In terms of their atomic / molecular structure, what are the Group 7 elements known as?

Answer 31

DIATOMIC MOLECULES (pairs of atoms, e.g. Br2)

Question 32

As you go down Group 7, the halogens:
become ______ REACTIVE
have a _________ MELTING POINT
have a __________ BOILING POINT

Answer 32

As you go down Group 7, the halogens:
become LESS REACTIVE
have a HIGHER MELTING POINT
have a HIGHER BOILING POINT

Question 33

How can the trend in reactivity of the halogens be shown?

Answer 33

By their DISPLACEMENT REACTIONS and their reactions with alkali and iron

Question 34

If M represents a halogen, what is the symbol

Answer 34

sss