Lecture 2 Flashcards
Examples of noble gases?
Helium, neon, argon and krypton
Characteristics of noble gases
Colorless gases, which occur naturally in air
Monatomic- they exist as single atoms
Unreactive
Uses of noble gases?
Helium= balloons
Argon= filler in tungsten filament also to protect metals being welded.
Neon= advertising signs
Krypton=lasers
Xenon=car headlamps/ hosiptal operating rooms
4 examples of halogens
fluorine, chlorine, bromine and iodine.
Characteristics of halogens
Form coloured gases
Are poisonous
Form diatomic molecules
What colour gases do halogens make?
Fluorine=pale yellow
chlorine=green
bromine=red
iodine=purple
Fluorines reaction with iron wool
iron wool bursts into flame- without any heating
Chlorines reaction with iron wool
Glows brightly
Bromines reaction with iron wool
glows less brightly
Iodines reaction with iron wool
shows a faint red glow
What happens when chlorine water is added to a colorless solution of potassium bromide?
Turns orange
What does chlorine displace bromine from?
Chlorine displaces bromine from aqueous potassium bromide.
What happens when chlorine water is added to a colorless solution of potassium iodine?
It turns red-brown.
4 examples of transition metals
Iron, tin, copper and silver
Physical properties of transition metals
Hard, tough and strong
High melting points
Malleable
Good conductors
High density
Chemical properties of transition metals
Much less reactive than group 1
Unreactive
ForM coloured compounds
They can form more than one compound with another element
Can form complex ions
Uses of transition metals
Building/bridges
Steel=radiators
Iron=alloys such as steel
Acts as catalysts
How does the electronic configuration of an element relate to its position in the modern periodic table? Explain with one example.
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.
How to know whether an element is metallic?
Francium is the most metallic. Metallic properties decrease going up the groups and increases from right to left.
How does electro positivity differ in the periodic table?
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.
