C2

Question 1

How were elements arranged in the early 1800s?

Answer 1

The known elements were arranged in order of atomic weight, which meant a periodic pattern was noticed in the properties of the elements, where the name ‘periodic table’ comes from. Here, scientists had no idea of atomic structure or of protons, neutrons or electrons

Question 2

Mendeleev’s involvement in Periodic table

Answer 2

1)Mendeleev put the elements mainyl in order of atomic weight but did switch that order if the properties meant it should be changed.
2) Gaps were left in the table to indicate the existence of undiscovered elements, allowing Mendeleev to predict what their properties might be and these elements often fitted this pattern.

Question 3

How did the discovery of isotopes prove Mendeleev’s theory on the periodic table

Answer 3

The discovery of isotopes confirmed Mendeleev was correct to not place elements in a strict order of atomic weight, but also to take account of their properties. Isotopes of the same element have different masses, but the same chemical properties so occupy the same position on the periodic table

Question 4

Alkali metal

Answer 4

Very reactive
Soft
Low density
So easy to lose outer electron they only ever react to form ionic compounds, white solids dissolving in water to form colourless solutions

Question 5

Trends for alkali metals

Answer 5

Increasing reactivity going down group
Lower melting and boiling points going down group
Higher relative atomic mass going down group

Question 6

Group 1 Metal reactions with water

Answer 6

They produce hydrogen and hydroxides that dissolve in water to give alkaline solutions

Question 7

Alkali metals reaction with chlorine

Answer 7

Group 1 Metals react vigorously when heated in chlorine gas to form white salts called metal chlorides,

Question 8

How do Group 1 Metals react with oxygen?

Answer 8

They react with oxygen to form a metal oxide

Question 9

What does lithium form when reacting with oxygen?

Answer 9

Lithium oxide

Question 10

What does sodium form when reacting with oxygen?

Answer 10

A mixture of:
Sodium oxide
Sodium peroxide

Question 11

What does potassium form when reacting with oxygen?

Answer 11

A mixture of potassium peroxide and potassium superoxide

Question 12

Halogen coloured vapours

Answer 12

Fluorine - poisonous yellow gas
Chlorine - poisonous dense green gas
Bromine - poisonous, red-brown volatile liquid
Iodine - dark-grey crystalline solid or a purple vapour

Question 13

Trends going down Group 7

Answer 13

Halogens:
Become less reactive
Have higher melting and boiling points
Have higher relative atomic masses

Question 14

Compounds formed by halogens

Answer 14

Hapogen atoms share electrons via covalent bonding with other non-metals to achieve a full outer shell, these compounds have simple molecular structures

Question 15

Group 0 elements properties

Answer 15

Inert - don’t react with much at all
Monatomic gases - single atoms not bonded to each other
Colourless gases at roon temperature

Question 16

Trends in noble gases

Answer 16

As you go down the group:
The boiling points of the noble gases increase as you move down the group along with increasing relative atomic mass, due to in an increase in the number of electrons in each atom leading to greater intermolecular forces between them which need to be overcome.

Question 17

Reaction between sodium and water:

Answer 17

2Na(s)+2H2O(l): 2NaOH(aq)+H2(g)

Question 18

Reaction between potassium and water

Answer 18

2K(s)+2H2O(l): 2KOH(aq)+H2(g)

Question 19

Alkali metal reaction with oxygen

Answer 19

4Na(s)+ O2(g): 2Na2O(s)