GK
CHEMISTRY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
atomic mass
|
|
|
atomic number
|
|
|
valence electrons
|
|
|
number of isotopes
|
Detailed explanation-1: -In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom.
Detailed explanation-2: -In the modern periodic table, the elements are arranged according to their atomic number-not their relative atomic mass . In the periodic table the elements are arranged into: rows, called periods, in order of increasing atomic number. vertical columns, called groups, where the elements have similar properties.
Detailed explanation-3: -In Mendeleev’s periodic table, elements are arranged in an increasing order of their atomic number.
Detailed explanation-4: -The number of electrons in an element is fixed. No two elements can have the same atomic number. Hence, elements can be easily classified in the increasing order of their atomic numbers.