chapter 14 - the periodic table

Question 1

what group 1 elements called?

Answer 1

alkali metals

Question 2

name 3 physical properties of alkali metals

Answer 2

• are soft and can be cut easily
• have low melting and boiling points
• have low densities (lithium, sodium and potassium float on water)

Question 3

going down the group, how do the densities, melting points and size of atoms, and reactivity change?

Answer 3

melting points decrease
densities increase
size of atoms increases
reactivity increases

Question 4

name a chemical property of alkali metals

Answer 4

• highly reactive

Question 5

what are group 17 elements called? (and what molecules? are they metal or non-metal?)

Answer 5

halogens

they are diatomic molecules and non-metals

Question 6

name 2 physical properties of halogens

Answer 6

• have low melting and boiling points
• are coloured

Question 7

chemical properties of halogens

Answer 7

• are reactive non-metals
• has 7 valence electrons
• react with metals to form halides
• undergo displacement reactions with halide solutions

Question 8

going down the group, how does reactivity and the size of atoms change?

Answer 8

reactivity decreases
the size of atoms increases

Question 9

define displacement reaction

Answer 9

displacement reaction is a reaction which one element takes the place of another element in the compound

Question 10

what are group 18 elements called? (and what molecules? are they metal or non-metal?)

Answer 10

noble gases

they are monoatomic and non-metals

Question 11

physical properties of noble gases

Answer 11

• colourless gases at room temperature
• have low melting and boiling points
• insoluble in water

Question 12

chemical properties of noble gases

Answer 12

• unreactive (because they have a filled valence shell)
• have 8 valence electrons except helium
• rarely react to form compounds (because they do not/gain/share electrons)

Question 13

what are the block of metals found in group 3-11 of the periodic table?

Answer 13

transition metals

Question 14

properties of transition metals

Answer 14

• high melting and boiling point
• high density
• variable oxidation states
• coloured compounds
• catalysts