group 7- the halogens

Question 1

how many electrons do group 7 elements have on their outer energy level/shell?

Answer 1

7 electrons

Question 2

what happens if we take 2 atoms of a group 7 element and let react?

Answer 2

group 7 elements form molecules with 2 atoms joined by a covalent bond

Question 3

what is covalent bonding?

Answer 3

the sharing of 2 electrons in order to achieve a full outer energy level

Question 4

a fluorine molecule consists of 2 atoms, how can we represent the molecule?

Answer 4

F—F

Question 5

how do the melting and boiling points of group 7 elements change as we move down the group?

Answer 5

the mp and bp increase as we move down the group

Question 6

what does the melting and boiling point tell us about an element?

Answer 6

their physical state

a gas, a liquid or a solid at room temperature

Question 7

around what temperature is room temperature?

Answer 7

20°C

Question 8

the boiling point of fluorine is -188
the boiling point of chlorine is -29
what does this tell us about their physical state at room temperature?

Answer 8

they are both gases at room temperature because they’re boiling points are lower than 20°C

Question 9

when an elements both boiling point and melting point is lower than 20°C
what is their physical state at room temperature?

Answer 9

a gas

Question 10

when an elements melting point is lower than 20°C but it’s boiling point is higher than 20°C
what is the elements physical state at room temp?

Answer 10

liquid

Question 11

when an elements both melting point and boiling point is higher than 20°C, what is their physical state at room temperature?

Answer 11

a solid

Question 12

what does F—F or C—C represent?

Answer 12

a covalent bond

Question 13

what is covalent bonding for?

Answer 13

atoms in an element aiming to achieve a full outer energy level by sharing electrons

Question 14

when group 7 elements react with other NON-metals, what occurs

Answer 14

covalent compounds

Question 15

represent the symbol for a covalent compound of Hydrogen and Chlorinde

Answer 15

H—Cl

Question 16

what do group 7 elements form when reacting with

other non metals
metals

Answer 16

Covalent compounds
halogen + non-metal=covalent bonding

non metals + non metals= covalent bonds
metals + non-metals= 
ionic bonds
extra info :
metals+metals=
metallic bonding

Question 17

when any group 7 elements react with a metal, how many electrons are gained and what ion is produced?
how do we write these
(use e.g)

Answer 17

gains 1 electron
an ion of 1- is produced

Flouride = F^-
Chloride=Cl^-

Question 18

describe the reactivity series of the halogens

Answer 18

the elements get less reactive as we move down group 7
this is because
it gets harder to gain 1 electron as we move down the group

Question 19

why is it harder gaining an electron moving down group 7?

Answer 19

-the great distance between the negative electron and the positive nucleus because of shells
-shielding of internal electrons
both these factors reduce the attraction of the electron on the outer energy level and the positive nucleus meaning there is less reaction

Question 20

in displacement reactions of halogens, what is being displaced from what?

Answer 20

a more reactive halogen can displace a less reactive halogen from an aqueous solution of its own salt

Question 21

what does an aqueous solution mean?

Answer 21

dissolved in water

Question 22

in a displacement reaction, how would

sodium bromide+fluorine be displaced?

Answer 22

sodium fluorine + bromine

bromine is less reactive than fluorine. Fluorine displaces it

Question 23

what is the displacement reaction of

potassium iodide+chlorine

Answer 23

potassium chlorine + iodine

chlorine is much more reactive than iodine.Chlorine displaces iodine

Question 24

what happens to lithium chloride + bromine in a displacement reaction?

Answer 24

no reaction

chlorine is already more reactive than bromine as it’s higher up in group 7.no displacement is taken place.