Atomic number is same as the number of protons in the element which is further equal to the number of electrons. As the number of electrons increases in the element, the atomic number of the element also increases.
In periodic table, elements are arranged in the groups, and these groups are columns starting from 1 to 18, elements are arranged in increasing order of atomic number. Elements are placed with difference of one atomic number.
First four elements present in the periodic table is:
atomic number is one (1).
atomic number is two (2).
atomic number is three (3).
atomic number is four (4).
Thus, the series of atomic numbers that represents the ordering of consecutive elements within the periodic table is the last option - 1, 2, 3, 4...
<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles. We calculate as follows:
0.340 mol Br2 ( </span>6.022 x 10^23 molecules / mol ) = 2.05 x 10^23 molecules
Molarity is defined as the ratio of number of moles to the volume of solution in litres.
The mathematical expression is given as:
Here, molarity is equal to 1.43 M and volume is equal to 785 mL.
Convert mL into L
As, 1 mL = 0.001 L
Thus, volume = 
= 0.785 L
Rearrange the formula of molarity in terms of number of moles:
n = 
= 1.12255 mole
Now, Number of moles = 
Molar mass of potassium hydroxide = 56.10 g/mol
1.12255 mole = 
mass in g = 
= 62.97 g
Hence, mass of 
= 62.97 g
Protons are held inside nucleous with neutrons with large amount of force. So mere rubbing doesn't help in breaking the nucleous of an atom. But electrons are far from the nucleous and the force of attraction is smaller. So electrons can jump readily while protons can't
