2n² rule:
This rule is used to determine number of electrons in particular shell.
n=1 means K shell
n=2 means L shell
n=3 means M shell
n=4means N shell
The first K shell can hold upto 2 electrons, L shell can hold up to 8, third M shell can hold up to 18and the fourth N shell can hold upto 32 electrons. This rule of arrangement of electrons according to the shell is known 2n2 rule where n means number of shell.
For example: There is one proton in the nucleus of hydrogen atom, which moves in K shell path. It has no neutron.
Selectively Permeable means that some things can move across the cell membrane while others cannot.
Here is a sentence: Because of the selectively permeable membrane, the germs were kept out while the food went in.
Answer:
2 atoms of nitrogen are present.
Answer:
1 grams Carbon Dioxide = 0.022722366761722 mole using the molecular weight calculator and the molar mass of CO2.
Explanation:
its a starter
is having lowest oxidation number of sulphur in teh options given. The oxidation number is -2.
The correct option is E.
Explanation:
have oxidation number of -2, which is lowest in all the options given.
In the given examples 
will have oxidation number zero because it is in elemental form. In the rules for oxidation number it is given that any element in free state has its oxidation number zero.
All other options are in compound form as:
S
= oxidation number is +4. It is calculated as oxygen having O.N of -2,
The charge on the atom is -2, so sum of the oxidation numbers of all the elements should be equal to -2.
x+3(-2)= -2
x = 4
S
= The charge on the atom is -2, so sum of the oxidation numbers of all the elements should be equal to -2.
x +4(-2) = -2
x = +6
The charge on the atom is -2, so sum of the oxidation numbers of all the elements should be equal to -2.
2x + 3(-2) = -2
2x = 4
x = 2
= oxidation number is -2 as the charge on ion in equal to its oxidation number.
