The first member of lanthanoid series is lanthanum.

Important Questions on Periodic Classification of Elements

MEDIUM

10th CBSE

IMPORTANT

Eduwiser's CBSE Chemistry For Class X>Chapter 5 - Periodic Classification of Elements>Exercise 7>Q 18

Third group of the periodic table accommodates maximum number of elements.

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE Chemistry For Class X>Chapter 5 - Periodic Classification of Elements>Exercise 7>Q 19

Mendeleev's periodic law was based on atomic number of the elements.

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE Chemistry For Class X>Chapter 5 - Periodic Classification of Elements>Exercise 7>Q 20

Zero group was not present in the table when Mendeleev presented it.

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE Chemistry For Class X>Chapter 5 - Periodic Classification of Elements>Exercise 7>Q 21

Every period of the periodic table starts with a member of alkali metal group.

HARD

10th CBSE

IMPORTANT

Eduwiser's CBSE Chemistry For Class X>Chapter 5 - Periodic Classification of Elements>Exercise 7>Q 22

The $\mathrm{d}$-block elements have fixed valency.

HARD

10th CBSE

IMPORTANT

Eduwiser's CBSE Chemistry For Class X>Chapter 5 - Periodic Classification of Elements>Exercise 7>Q 23

In the lanthanoid series the electrons occupy $4\mathrm{f}-$ orbitals in preference of $5\mathrm{d}-$ and $6\mathrm{p}-$ orbitals.

MEDIUM

10th CBSE

IMPORTANT

Eduwiser's CBSE Chemistry For Class X>Chapter 5 - Periodic Classification of Elements>Exercise 7>Q 24

Seventh period of periodic table is incomplete.

EASY

10th CBSE

IMPORTANT

Eduwiser's CBSE Chemistry For Class X>Chapter 5 - Periodic Classification of Elements>Exercise 7>Q 25

First period contains only 2 elements.