SSLC (English Medium) Class 9 - Tamil Nadu Board of Secondary Education Question Bank Solutions for Science

Write short notes on Halley’s comet.

d-block elements are otherwise known as ______.

If the electronic configuration of an element is 1s² 2s² 2p⁶ 3s² 3p¹’then it will
occupy ______ block of the periodic table.

f-block elements are also known as ______.

______ block element is placed at the bottom of the periodic table. 

What are the s-block elements?

What are the p-block elements

Group 1 (except hydrogen) elements are called alkali metals.

d-block elements are called transition elements.

Group 3-12 elements in the modern periodic table are called d block elements.

Assertion (A): Group 2 elements in the modem periodic table are called alkaline earth metals.
Reason (R): The oxides of group 2 elements produce alkaline solutions when they are dissolved in water.

Assertion (A): Noble gases are chemically inert in nature.
Reason (R): Noble gases have stable electronic structures.

Atoms are so tiny their mass number cannot be expressed in grams but expressed in ______.

The ratio of masses of H and O in H₂O is ______.

Why is the term basicity is used for acids?

The antiseptic used for cleansing the wounds is ______.

Antiseptics are used internally to treat infections of the ______ and ______.

Assertion (A): Antiseptic is a substance that prevents infections caused by disease-causing pathogens.
Reason (R): Antiseptics either kill the microorganism or prevent their growth.

How are antiseptics used?

How is the body wall of coelenterates arranged?