1.2: The periodic table

Question 1

How are elements arranged in the periodic table?

Answer 1

● Elements​ ​are​ ​arranged​ ​in​ ​order​ ​of​ ​atomic​ ​(proton)​ ​number​ ​(smaller​ ​number)​ ​and​ ​so that​ ​elements​ ​with​ ​similar​ ​properties​ ​are​ ​in​ ​columns,​ ​known​ ​as​ ​groups.

● Elements​ ​in​ ​the​ ​same​ ​periodic​ ​group​ ​have​ ​the​ ​same​ ​amount​ ​of​ ​electrons​ ​in​ ​their outer​ ​shell,​ ​which​ ​gives​ ​them​ ​similar​ ​chemical​ ​properties.

Question 2

How did Mendeleev arrange his periodic table?

Answer 2

● Ordered​ ​his​ ​table​ ​in​ ​order​ ​of​ ​atomic mass,​ ​but​ ​not​ ​always​ ​strictly​ ​–​ ​i.e.​ ​in some​ ​places​ ​he​ ​changed​ ​the​ ​order based​ ​on​ ​atomic​ ​weights.
● Left​ ​gaps​ ​for​ ​elements​ ​that​ ​he thought​ ​had​ ​not​ ​been​ ​discovered yet.

Question 3

What are examples of differences between metals and non-metals?

Answer 3

● Metals​ ​=​ ​elements​ ​that​ ​react​ ​to​ ​form​ ​positive​ ​ions.
o Majority​ ​of​ ​elements​ ​are​ ​metals.
o Found​ ​to​ ​the​ ​left​ ​and​ ​towards​ ​the​ ​bottom​ ​of​ ​the​ ​
periodic​ ​table.

● Non-metals​ ​=​ ​elements​ ​that​ ​do​ ​not​ ​form​ ​positive​ ​ ions.
o Found​ ​towards​ ​the​ ​right​ ​and​ ​top​ ​of​ ​the​ ​periodic​ ​
table.

Question 4

What are the characteristics of Group 1 elements?

Answer 4

● Metals​ ​in​ ​group​ ​one​ ​react​ ​vigorously​ ​with​ ​water​ ​to​ ​create​ ​an​ ​alkaline​ ​solution​ ​and hydrogen.
● They​ ​all​ ​react​ ​with​ ​oxygen​ ​to​ ​create​ ​an​ ​oxide.
● They​ ​all​ ​react​ ​with​ ​chlorine​ ​to​ ​form​ ​a​ ​white​ ​precipitate.
● The​ ​reactivity​ ​of​ ​the​ ​elements​ ​increases​ ​going​ ​down​ ​the​ ​group

Question 5

What are the characteristics of elements in Group 0?

Answer 5

● They​ ​are​ ​unreactive​ ​and​ ​do​ ​not​ ​easily​ ​form​ ​molecules, because​ ​they​ ​have​ ​a​ ​stable​ ​arrangement​ ​of​ ​electrons (full​ ​outer​ ​shell).
● The​ ​boiling​ ​points​ ​of​ ​the​ ​noble​ ​gases​ ​increase​ ​with​ ​increasing​ ​relative​ ​atomic​ ​mass
(going​ ​down​ ​the​ ​group).

Question 6

What are the characteristics of elements in Group 7?

Answer 6

● as​ ​you​ ​go​ ​down​ ​the​ ​group,​ ​relative​ ​molecular​ ​mass,​ ​melting​ ​point​ ​and​ ​boiling​ ​point
all​ ​increase
● reactivity​ ​decreases​ ​down​ ​the​ ​group