chap 11 periodic table

Question 1

what is the periodic table

Answer 1

list of elements arranged in increasing proton number

Question 2

what are the metallic properties of elements across a period

Answer 2

elements change from metals to non metals

there is a decrease in metallic properties and increase in non metallic properties

an atom displays more metallic properties when it is more likely to lose electrons than gaining electrons because it requires more energy to lose electrons as there are more protons in the nucleus

Question 3

what are the metallic properties of elements down a group

Answer 3

there is an increase in metallic properties and a decrease in non metallic properties

size of atom increases hence outermost electrons are further away from the attractive force of the nucleus

an atom further down the group loses its outermost electrons more easily

Question 4

what are the physical properties of alkali metals/grp 1 elements

Answer 4

soft and can be cut easily
low mp bp
low densities - li na k float on water

going down the group
- mp decrease
- densities increase

Question 5

what are the chemical properties of alkali metals

Answer 5

very reactive and is stored in soil to prevent them from reacting with air and water

Question 6

reaction when lithium reacts with water

Answer 6

reacts quickly
lithium floats on water
lithium + water -> lithium hydroxide + hydrogen gas

Question 7

reaction when potassium reacts with water

Answer 7

reacts very violently to form potassium hydroxide and hydrogen gas

reaction is explosive

Question 8

reaction when sodium reacts with water

Answer 8

reacts violently to form sodium darts around water surface

hydrogen gas may catch fire and explode

sodium + water -> sodium hydroxide + hydrogen gas

Question 9

what are group 17 elements/ halogens

Answer 9

exist as diatomic molecules with 2 halogen atoms per molecule
non metals

Question 10

what are the physical properties of halogens

Answer 10

low mp bp

coloured

down the group
- mp bp increase
- colours become darker as colour intensities increase

Question 11

what are the chemical properties of halogens

Answer 11

reactivity decreases down the group
size of atom increases down the group hence more difficult for nucleus to attract one more electron

undergo displacement reactions with hallide solutions

Question 12

what is the order of reactivity of group 17 elements

Answer 12

F > Cl > Br > I > At > Ts

Question 13

what is a displacement reaction

Answer 13

an element takes place of another element in the compound

a more reactive halogen will displace a less reactive halogen from its hallide solution

Question 14

what is a hallide solution

Answer 14

salts of halogens

Question 15

what is the displacement reaction of Cl2 and KBr, KI

Answer 15

KBr:
- chloride displaces bromine from bromide solution

KI:
- chlorine displaces iodine from an iodide solution

Question 16

what is the displacement reaction of Br2 and KCl and KI

Answer 16

KCl: no reaction

KI: bromine displaces iodine from an iodide solution

Question 17

what is the displacement reaction of I2 and KCl and KBr

Answer 17

no reaction

Question 18

what are properties of noble gases

Answer 18

monoatomic non metals - one atom per molecule

colourless gases at room temp

low mp bp

insoluble in water

unreactive as they have full valence shells of electrons and hence do not gain/lose/share electrons and rarely react to form compounds