topic 2 recap Q. periodic table

Question 1

how is the modern periodic table ordered?

Answer 1

by atomic number

Question 2

how were the early lists of elements ordered?

Answer 2

by atomic weight

Question 3

why did mendeleev swap the order of some elements?

Answer 3

to group them by their chemical properties

Question 4

Why did Mendeleev leave gaps in his periodic table?

Answer 4

to leave room for elements that has not been discovered

Question 5

Why do elements in a group have similar chemical properties?

Answer 5

they have the same number of electrons in their outer shell

Question 6

What name is given to group 1 elements?

Answer 6

alkali metals

Question 7

Why are alkali metals names this?

Answer 7

they are metals that will react with water to form an alkali

Question 8

give the general equation for the reactions of alkali metals with oxygen, chlorine and water

Answer 8

metal + oxygen = metal oxide
metal + chlorine = metal chloride
metal + water = metal hydroxide + hydrogen

Question 9

How does the reactivity of the alkali metals change down the group?

Answer 9

increases (more reactive)

Question 10

Why does the reactivity of the alkali metals increase down the group?

Answer 10

larger atoms
outer electrons are further from nucleus
weak electrostatic forces
easier to lose electron

Question 11

What name is given to group 7 elements?

Answer 11

halogens

Question 12

Give the formulae of the first 4 halogens.

Answer 12

F2
Cl2
Br2
I2

Question 13

Why does the reactivity of the halogens increase up the group?

Answer 13

smaller atoms
outer shell is closer to the nucleus
strong electrostatic forces of attraction
easier to gain electron

Question 14

How does the reactivity of halogens change down the group?

Answer 14

decrease (less reactive)

Question 15

Why are noble gases inert?

Answer 15

they have a full outer shell so they dont need to gain or lose electrons

Question 16

What is a displacement reaction?

Answer 16

when a more reactive element takes the place of a less reactive element in a compound

Question 16

How does the melting points of the halogens change down the group?

Answer 16

increase (higher melting point)

Question 17

What name is given to group 0 elements?

Answer 17

noble gases

Question 17

why can transition metals be used as cataylsts?

Answer 17

variable oxidation states. e.g Fe2+ and Fe3+

Question 18

how does the reactivity of the halogens change down the group?

Answer 18

decrease (less reactive)

Question 19

how does the melting point of transition metals compare to those of group 1 metals?

Answer 19

transition melting points are higher

Question 20

Give the properties of transition metal compounds?

Answer 20

they form ions with different charges and coloured compounds.

Question 21

what is the difference between the charges of transition metal ions and group 1 ions?

Answer 21

transition metals can form different charges, group 1 metals can only form +1 ions.

Question 22

How does the density of transition metals compare to that of group 1

Answer 22

transition metals are more dense, strong and hard

Question 23

what are transition metals used for

Answer 23

cataylsts