EASY
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What is meant by period in a periodic table?

Important Questions on Periodic classification of elements

EASY

Besides gallium, which other elements have since been discovered those were left by Mendeleev in his Periodic Table? (Any two) 

EASY
What were the criteria used by Mendeleev in creating his Periodic Table?
EASY
What are the vertical columns in the periodic table called? 
MEDIUM
The number of Groups in Mendeleev's Periodic table was:
EASY

Give any two limitations of Mendeleev's periodic classification.

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Elements in Mendeleev’s periodic table have been arranged according to: 
 
MEDIUM

Write two achievements and two anomalies of Mendeleev's periodic table.

EASY
Among the following reactions of hydrogen with halogens, the one that requires a catalyst is:
HARD
Use Mendeleev's Periodic table to predict the formulae for the oxides of the following elements: K, C, Al, Si
EASY

Why do you think the noble gases are placed in a separate group? 

MEDIUM

Write merits of Mendeleev's periodic table. 

MEDIUM

An element X form an oxide X2O3. In which group of Mendeleev's periodic table, is this element X.

 

MEDIUM

Use Mendeleev's Periodic Table to predict the formulae for oxides of the following elements: 

K and Al

MEDIUM

Which of the following statement are incorrect regarding Mendeleev's periodic table?

(a) Mendeleev considered compounds formed by elements with oxygen and hydrogen.

(b) In the table Ni is placed before Co

(c) Eka-silicon in Mendeleev's periodic table is gallium

(d) The properties of the elements are periodic functions of their atomic masses.

HARD
B has a smaller first ionization enthalpy than Be. Consider the following statement:
(I) it is easier to remove 2p electron than2s  electron
(II) 2p electron of B is more shielded from the nucleus by the inner core of electrons than the 2s electrons of Be
(III) 2s electron has more penetration power than 2p electron
(IV) atomic radius of B is more than Be
(atomic number B:5, Be=4 )
The correct statements are.
EASY
What were the criteria used by Mendeleev in creating his periodic table? 
MEDIUM
State two demerits of Mendeleev's classification of elements.
EASY
According to Mendeleev's periodic law, properties of elements are periodic function of their _____