The video discusses the concept that matter cannot be divided indefinitely, leading to the idea of atoms as the smallest unit. This concept was revived in the early 1800s by John Dalton, who studied gases and developed the atomic theory. Dalton concluded that elements are made of atoms, which are identical within an element but differ between elements. He also stated that atoms cannot be transformed into different atoms through chemical reactions and that compounds form by combining atoms of different elements. These ideas form the basis of modern atomic theory.

What was the belief about matter that was forgotten until the early 1800s?

• Matter was made of fire and water.

• Matter was composed of energy.

• Matter could not be divided infinitely.

• Matter could be divided infinitely.

Who was the chemist that began studying gases to understand weather activities?

• Albert Einstein

• Marie Curie

• John Dalton

• Isaac Newton

According to Dalton, what are elements made of?

• Compounds

• Molecules

• Atoms

• Ions

What did Dalton conclude about atoms of the same element?

• They are exactly alike.

• They are different from each other.

• They are made of smaller particles.

• They can change into different atoms.

How are compounds formed according to Dalton's theory?

• By heating elements to high temperatures.

• By joining atoms of two or more elements.

• By splitting atoms of a single element.

• By mixing molecules of the same element.