The Modern Periodic Table

Define Dalton's atomic theory.

Assertion (A) : Sixth period is the longest period in the periodic table.

Reason (R) : Sixth period involves the filling of all the orbitals of the sixth energy level.

An element has configuration $2, 8, 1$. It belongs to,

Arrange the following in proper order of atomic size

All the lanthanoids and actinoids belong to group _____ of the periodic table.($3/4$).

Among the elements from atomic number $1$ to $36$, the number of elements which have an unpaired electron in the $\mathrm{s}$-subshell is $6$.

The first member of lanthanoid series is lanthanum.

All the lanthanoids and actinoids belong to group _____ of the periodic table.($3/4$)

Elements having the similar outer electronic configuration in their atoms are arranged in the same _____.

In the modern periodic table, the elements are arranged in the increasing order of their _____.

The modern periodic table is based on increasing atomic mass.

The fifteen elements from Lanthanum to Lutetium are named as _____

An element has its electronic configuration as 2, 8, 2. To which period does this element belong?

An element has its electronic configuration as 2, 8, 2. What is the group of this element?

An element has its electronic configuration as 2, 8, 2. The atomic number of this element is _____.

In Lanthanoid series, the element well known to exhibit $+4$ oxidation state is

Name the metalloid element belonging to the same period to which germanium belongs.

What is the significance of a periodic table?

What is a periodic table? Explain.

According to modern periodic law, the properties of the elements are in periodic function of their _____.