CBSE Quiz

The sum of number of elements present in the 2nd period and 3rd period of the modern periodic table is -------

A nonmetal X reacts violently when exposed to air. The group number of the element is

The number of valence electrons present in the rogue element of the periodic table is ----

When Mendeleev started his work, ------ elements were known.

The modern periodic table is based on

• Atomic number

• Atomic mass

• Atomic radius

• Atomic density

Identify the wrong statement among the following.

• Dry HCl do not changes the color of blue litmus paper

• Zno reacts only with NaOH

• Acetic acid is a weak acid as it undergoes partial dissociation

• When Zn reacts with NaOH, there is a evolution of hydrogen gas

Eka-boron stands for element X. The correct chemical symbol of X is ------

Eka-aluminum stands for

Identify the wrong statement among the following

• P shows variable valency

• The valence electrons present in nitride ion is 8

• Out of all elements in 2nd period of the modern periodic table, Ne has least size.

• Melting point of NaCl is more than melting point of CaO

Which of the following is a metalloid?

• Si

• C

• Na

• Pt