The Periodic Table Flashcards
Examples of noble gases
Helium,neon,argon,krypton,xenon,radon
Uses of helium
Used in ballons and airship
Uses of argon
Filling light bulb
Use of neon
Lamps and advertisment signs
Why they replaced hydrogen with helium?
Because hydrogen is flammable but helium is not
Why argon used in filling light bulbs?
Because it is an inert atmosphere that doesn’t lose or gain electrons easily and to protect the filament from burning
What is phisical properties of alkali metals?
-they have shiny silver surface
-They are soft
-they have low densities
-they have low melting point
They are good conductor of electricity and heat
What is melting point of lithium
180
What is melting point of potassium
64
Why lithium float on water?
Because they are less dense than water
Periodic table is obtained by arranging elements in order of_______
Increase atomic number
How many elements in group and how many found in nature
116
92 found in nature
How many periods and groups in periodic table
7 periods
8 main group
All elements in same period have _______
Same number of energy shells
Why number of electrons in the valence shell increases by one?
Because atomic number increase by one which leads to periodicity in chemical properties across the period
Why elements in the same group have same chemical properties
Because they have same number of electrons in the valence shell which is equal to group’s number
What is a period’s number
Number of shells filled with electrons
What is group’s number
Number of electrons in the outermost shell
Examples of gas element
Hydrogen, nitrogen, oxygen, fluorine, chlorine, noble gases
Example of liquid metal
Mercury
Example of liquid non metal
Bromine
Why atoms of all elements tend to combine with each other
In order to get the electronic structure of the nearest Noble gas
Why Carbon and silicon don’t form ions?
As the maximum number of electrons that can be lost or gained is only three electrons
Why hydrogen is difficult to place it in periodic table?
Because it is smallest atom of all it’s properties are distinctive,unique and doesn’t fit easily
