The Modern Periodic Table

Hydrogen resembles alkali metals as well as halogens. Explain.

How electronic configuration of the transition elements different from that of the non-transition elements?

Which of the following is correct about compound $\mathrm{X}$ (Atomic number $=18$)?

Arrange $\mathrm{B}\mathrm{e},\mathrm{}\mathrm{M}\mathrm{g},\mathrm{}\mathrm{C}\mathrm{a},\mathrm{}\mathrm{S}\mathrm{r}$ in the ascending order of ionisation enthalpy.

The family of elements having seven electrons in the outermost shell is:

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

The correct order of $1^{\mathrm{st}}$ ionisation enthalpy among the following elements $\mathrm{Be}, \mathrm{B}, \mathrm{C}, \mathrm{N}, \mathrm{O}$ is

Which pair of atomic numbers represents s-block elements?

The correct order of $1^{\mathrm{st}}$ ionisation enthalpy among the following elements $\mathrm{Be}, \mathrm{B}, \mathrm{C}, \mathrm{N}, \mathrm{O}$ is

Identify the element that has the lower ionisation energy in each pair of the following.

$\mathrm{K}$, $\mathrm{Br}$

Identify the element that has the lower ionisation energy in each pair of the following.

$\mathrm{Br}$, $\mathrm{F}$

Identify the element that has the lower ionisation energy in each pair of the following.

$\mathrm{Li}$, $\mathrm{O}$

Identify the element that has the lower ionisation energy in each pair of the following.

$\mathrm{Mg}$, $\mathrm{Na}$

Explain why ${\mathrm{Gd}}^{+3}$ is colourless.

What are trans-uranic elements? Write their names.

What are actinoids?

Explain the position of actinoid.

Write the charge on nucleus, ${}_7\mathrm{N}^{14}$ in coulomb. Take, $e=1.6\times {10}^{-19} \mathrm{C}$

What is mischmetal? Write its one use.

Define transuranic elements.