HARD
11th CBSE
IMPORTANT
Earn 100

The order of screening effect of electrons of and orbitals of a given shell of an atom on its outer shell electrons is:
(a)
(b)
(c)
(d)

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Important Questions on Classification of Elements and Periodicity in Properties
EASY
11th CBSE
IMPORTANT
The first ionisation enthalpies of and are in the order:

HARD
11th CBSE
IMPORTANT
The electronic configuration of gadolinium (Atomic number ) is

MEDIUM
11th CBSE
IMPORTANT
The statement that is not correct for periodic classification of elements is:

MEDIUM
11th CBSE
IMPORTANT
Among halogens, the correct order of the amount of energy released in electron gain (electron gain enthalpy) is:

MEDIUM
11th CBSE
IMPORTANT
The period number in the long form of the periodic table is equal to

EASY
11th CBSE
IMPORTANT
The elements in which electrons are progressively filled in -orbital are called

MEDIUM
11th CBSE
IMPORTANT
Which of the following is the correct order of the size of the given species:

MEDIUM
11th CBSE
IMPORTANT
The formation of the oxide ion, , from oxygen atom requires first an exothermic and then an endothermic step as shown below:
Thus, the process of formation of In gas-phase Is unfavourable even though Is isoelectronic with neon. It Is due to the fact that,
