Lecture 2

Question 1

Examples of noble gases?

Answer 1

Helium, neon, argon and krypton

Question 2

Characteristics of noble gases

Answer 2

Colorless gases, which occur naturally in air
Monatomic- they exist as single atoms
Unreactive

Question 3

Uses of noble gases?

Answer 3

Helium= balloons
Argon= filler in tungsten filament also to protect metals being welded.
Neon= advertising signs
Krypton=lasers
Xenon=car headlamps/ hosiptal operating rooms

Question 4

4 examples of halogens

Answer 4

fluorine, chlorine, bromine and iodine.

Question 5

Characteristics of halogens

Answer 5

Form coloured gases
Are poisonous
Form diatomic molecules

Question 6

What colour gases do halogens make?

Answer 6

Fluorine=pale yellow
chlorine=green
bromine=red
iodine=purple

Question 7

Fluorines reaction with iron wool

Answer 7

iron wool bursts into flame- without any heating

Question 8

Chlorines reaction with iron wool

Answer 8

Glows brightly

Question 9

Bromines reaction with iron wool

Answer 9

glows less brightly

Question 10

Iodines reaction with iron wool

Answer 10

shows a faint red glow

Question 11

What happens when chlorine water is added to a colorless solution of potassium bromide?

Answer 11

Turns orange

Question 12

What does chlorine displace bromine from?

Answer 12

Chlorine displaces bromine from aqueous potassium bromide.

Question 13

What happens when chlorine water is added to a colorless solution of potassium iodine?

Answer 13

It turns red-brown.

Question 14

4 examples of transition metals

Answer 14

Iron, tin, copper and silver

Question 15

Physical properties of transition metals

Answer 15

Hard, tough and strong
High melting points
Malleable
Good conductors
High density

Question 16

Chemical properties of transition metals

Answer 16

Much less reactive than group 1
Unreactive
ForM coloured compounds
They can form more than one compound with another element
Can form complex ions

Question 17

Uses of transition metals

Answer 17

Building/bridges
Steel=radiators
Iron=alloys such as steel
Acts as catalysts

Question 18

How does the electronic configuration of an element relate to its position in the modern periodic table? Explain with one example.

Answer 18

The position of an element depends upon the number of valence electrons that rely on its electronic configuration. Those elements which have identical valence electrons occupy the same group. For example, elements with one valence electron belong to group 1.
The period number is equal to the number of shells.
For example, elements with one shell belong to period 1.

Question 19

How to know whether an element is metallic?

Answer 19

Francium is the most metallic. Metallic properties decrease going up the groups and increases from right to left.

Question 20

How does electro positivity differ in the periodic table?

Answer 20

As we move down in the modern periodic table, the size of the atom increases, decreasing the effective nuclear charge, thereby increasing the tendency to donate electrons. Thus, electro positivity rises as we move down in the modern periodic table.