Last week, we have discussed on the Common Properties of a Group (in general).
Today, let’s take a closer look at the properties of elements from 3 very important groups that examiners like to test you:
Properties of Impt Groups in Periodic Table:
Group I (Alkali Metals)
- Soft & Silvery Metals
- Low Densities & Low MPs
- Has 1 valence electron
- Forms ions with 1+ charge by giving away 1 valence electron
- Reacts vigorously with cold water to form metal hydroxide alkaline solution & hydrogen gas
- Reacts vigorously with chlorine gas to form ionic metal chlorides
Group VII (Halogens)
- Low BPs non-metals
- Exists as diatomic molecules
- Coloured compounds
- Has 7 valence electrons
- Forms ions with 1- charge by gaining 1 valence electron
- Reacts with metals for form ionic salts
- Halogens Displacement Rxn – more reactive halogen will displace less reactive halogens from halide solution
Group O (Noble Gases)
- Unreactive Gases
- Exists as Monatomic (single atom)
- Colourless gas @ rtp
- Full outer shell of electrons – stable!
- Low MPs and BPs
It’s time to put on your thinking caps and work on some exam-based questions (similar to GCE O Levels Chemistry Ten Years Series questions).
Question 1:
Astatine is the element at the bottom of Group VII.
Which statement below will not be true for astatine?A) Astatine exists as diatomic molecules
B) Astatine is a gas
C) Astatine forms negative ions
D) Astatine reacts with water to form alkaline solution & hydrogen gas
Question 2:
Argon is a noble gas.i) Give one use of argon
ii) Explain why it is used for this purpose.
iii) Referring to the Periodic Table, state the chemical name of the element that is in the same period as argon but is a metal which forms a positive ion with charge of 1+.
PS: Leave your answers in the comments section below to see how you fare! =)
Questions 1
A is the correct answer
Q#2 1- used in bulbs
2- unreactive, it dosen’t undergoes reaction with tungsten.
3- sodium Na+
Q#1 =] D , it is not true for astatine because its a non metal.
Alkaline solution is only formed when alkali metals reacts with cod water and release hydrogen gas!!
1.B
i.used in light bulbs
ii.Its used for this purpose because ,its an inert gas as a result it doesnot react with tungsten fillament as oxygen does
iii.neon
1.A
2.
i.used in light bulbs
ii.Its used for this purpose because ,its an inert gas as a result it doesnot react with tungsten fillament as oxygen does.
iii.Argon