Periodic Table Group 1 and 7

Question 1

What does the reaction produce when lithium, sodium, potassium are put in water?

Answer 1

• they react vigorously
• the reaction produces a metal hydroxide solution
• this solution is alkaline

Question 2

What is the word equation for sodium reacting with water?

Answer 2

sodium + water = sodium hydroxide + hydrogen

Question 3

What is the symbol equation for sodium reacting with water?

Answer 3

2Na + 2H20 = 2NaOH + H2

Question 4

What forms when the Group 1 metals also react with oxygen in the air?

Answer 4

• metal oxides
• eg lithium reacts to form lithium oxide
• sodium reacts to form a mixture of sodium oxide and sodium peroxide
• potassium reacts to form a mixture of potassium peroxide and potassium superoxide

Question 5

What is the reactivity as you go down Group 1?

Answer 5

• elements become more reactive

Question 6

In which order do the elements in Group 1 react?

Answer 6

• lithium takes longer than sodium or potassium to react so its the least reactive
• potassium takes the shortest time to react of these three elements, so it is the most reactive

Question 7

Why are the metals in Group 1 more reactive as you go down the group?

Answer 7

• all group 1 elements have 1 electron in their outer shell
• as you go down group 1 the outermost electron is in a shell that’s further from the nucleus
• so the attraction between the outermost electron and the nucleus becomes less
• as you go down group 1 the atoms get bigger, the outer electron is more easily lost, and the metal is more reactive

Question 8

What are the elements in group 7 called?

Answer 8

• the halogens

Question 9

What is chlorine at room temperature?

Answer 9

• chlorine is a fairly reactive poisonous green gas

Question 10

What is bromine at room temperature?

Answer 10

• bromine is a poisonous, red-brown liquid
• which gives off an orange vapour at room temperature

Question 11

What is Iodine at room temperature?

Answer 11

• iodine is a dark grey crystalline solid which gives off a purple vapour when heated

Question 12

What is chlorine, bromine and iodine’s state at room temperature?

Answer 12

chlorine- gas
bromine- liquid
iodine- solid

Question 13

What is chorine, bromine and iodine’s boiling point?

Answer 13

chlorine- -34 degrees
bromine- 59 degrees
iodine- 185 degrees

Question 14

Why does reactivity decrease going down group 7?

Answer 14

• all group 7 elements have 7 electrons in their outer shell
• they gain one electron to form a 1- ion
• the easier it is for a halogen atom to attract an electron, the more reactive the halogen will be
• as you go down group 7, the halogens become less reactive
• it gets harder to attract the extra electron to fill the outer shell when its further away from the nucleus

Question 15

What is displacement?

Answer 15

• where a more reactive element displaces a less reactive element from a compound

Question 16

What happens when you add chlorine water to potassium chloride solution?

Answer 16

• no reaction

Question 17

What happens when you add bromine water to potassium chloride solution?

Answer 17

• no reaction

Question 18

What happens when you add iodine water to potassium chloride solution?

Answer 18

• no reaction

Question 19

What happens when you add iodine water to potassium bromide solution?

Answer 19

• no reaction

Question 20

What happens when you add bromine water to potassium chloride solution?

Answer 20

• no reaction

Question 21

What happens when you add chlorine water to potassium bromide solution?

Answer 21

• orange solution Br2 is formed

Question 22

What happens when you add chlorine water to potassium iodide solution?

Answer 22

• brown solution I2 formed

Question 23

What happens when you add bromine water to potassium iodide solution?

Answer 23

• brown solution I2 formed

Question 24

What happens when you add iodine water to potassium iodide solution?

Answer 24

• no reaction

Question 25

What is an example of a displacement reaction equation between halogens and salt solutions?

Answer 25

Cl2 + 2KI = I2 + 2KCl

Cl2 + 2I = 2Cl + I2

• chlorine displaces iodine from potassium iodide
• chlorine is reduced and iodine is oxidised

Question 26

What is the loss of electrons?

Answer 26

• oxidation

Question 27

What is the gain of electrons?

Answer 27

• reduction

Question 28

What is the oxidising agent?

Answer 28

• accepts electrons and gets reduced
• chlorine is an oxidising agent (previous example)

Question 29

What is the reducing agent?

Answer 29

• donates electrons and gets oxidised
• so iodine is the reducing agent (previous example)