The Periodic Table

Question 1

John Newlands’ contribution

Answer 1

every eighth element had similar properties when arranged by atomic weight

Question 2

Dmitri Mendeleev’s contributions

Answer 2

• The elements are arranged in order of increasing atomic mass
• The horizontal rows are called periods
• The vertical columns are called groups
• Elements in the same group are similar to each other

Question 3

why did Mendeleev leave gaps

Answer 3

he was aware that not all elements had been discovered

Question 4

shell one

Answer 4

2 electron capacity

Question 5

shell two

Answer 5

8 electron capacity

Question 6

shell three

Answer 6

8 electron capacity

Question 7

period number

Answer 7

number of shells

Question 8

group number

Answer 8

number of electrons in outermost shell

Question 9

atomic number

Answer 9

total number of electrons in all shells

Question 10

group 0

Answer 10

(group 8) the noble gases

Question 11

physical properties of group 0

Answer 11

• non-metal elements
• low boiling points, but increase down the group
• stronger intermolecular forces going down (larger atoms)

Question 12

chemical properties of group 0

Answer 12

• extremely unreactive
• already have full outer shells

Question 13

group 1

Answer 13

alkali metals

Question 14

physical properties of group 1

Answer 14

• soft - can be cut with a knife
• low melting points, but decrease down the group
• low densities

Question 15

chemical reactions of group 1 in water

Answer 15

• reactions get more vigorous down the group
• effervescence
• melting in some cases
• will eventually fizz away and disappear
• burns with sparks from potassium downwards

Question 16

chemical reactions of group 1 with oxygen

Answer 16

• react with oxygen in the air to form metal oxides
• burn vigorously when heated - oxide forms as a white smoke
• forms a white oxide on surface of metal at room temperature

Question 17

reactivity of group 1

Answer 17

increases down the group

Question 18

chemical reactions of group 1 with chlorine

Answer 18

• react vigorously with chlorine to form chlorides
• chlorides are solids at room temperature
• chlorides dissolve in water to form colourless solutions

Question 19

why does reactivity increase down group 1

Answer 19

• each of its atoms loses its outer electron to form a positively charged
  ion
• The more easily the ions form the more reactive the metal

Question 20

group 7

Answer 20

the halogens

Question 21

physical properties of group 7

Answer 21

• all diatomic - exist as simple molecules
• melting points and boiling points increase down group 7 - stronger intermolecular forces (more energy required)

Question 22

chemical properties of group 7

Answer 22

• halogens react with metals to form salts - held together by ionic bonds
• reactivity decreases down the group

Question 23

group 7 displacement reactions

Answer 23

more reactive halogens can displace less reactive halogens