RD
MONDAY,3
JULY, 2020
TOPIC : TRENDS IN GROUP SEVEN AND EIGHT
OBJECTIVES
• Explain the trends in group eight
KEYWORDS
• Noble gases
• Monoatomic
unreactive
TREND IN GROUP 8 OR 0
• Group 8 elements are also called noble gases
• They include helium ,neon and argon
• They are all gases.The noble gases all form colourless gases at room
temperature.
• They are inert that is unreactive and do not form compounds .This is
because they have completely filled outermost shell
• They are monatomic, which means they exist as individual atoms. Most
other gases are diatomic.
• They do not normally form bonds with other elements
• Their density increases down the group
MELTING AND BOILING POINT
• Their melting and boiling point increases down the group .
ELEMENT
ATOMIC
NUMBER
ELECTRONIC
STRUCTURE
MASS
NUMBER
MELTING
POINT /O C
BOILING
POINT / OC
Helium ,He
2
2
4
-270
-269
Neon , Ne
10
2,8
20
-249
-246
Argon , Ar
20
2,8,8
40
- 189
-186
CLASS TASK
• Are halogens metals or non-metals ?
• What is the trend in their melting and boiling point
• Would you expect iodine to be more or less reactive than bromine
•
ADDITIONAL TASK
• What trend in melting point can be seen in group 8
• Suggest this group is called group 8