The video explains John Dalton's atomic theory, which posits that elements are made of indivisible atoms. Dalton believed atoms cannot be created or destroyed in chemical reactions, only rearranged. Compounds form from different atoms, and elements have unique masses and properties. Isotopes of the same element share chemical properties but differ in nuclear properties.

What did John Dalton propose about the nature of elements?

• Elements are made of indivisible particles called atoms.

• Elements are made of divisible particles called molecules.

• Elements are made of indivisible particles called molecules.

• Elements are made of divisible particles called atoms.

According to Dalton, what happens to atoms during a chemical reaction?

• They are destroyed.

• They are created.

• They are rearranged.

• They are transformed into energy.

What is formed when hydrogen gas reacts with nitrogen gas?

• Ammonia

• Nitric acid

• Water

• Hydrogen fluoride

Which of the following is true about the formation of compounds?

• Compounds are formed by the destruction of atoms.

• Compounds are formed by the combination of different types of atoms.

• Compounds are formed by the combination of the same type of atoms.

• Compounds are formed by the creation of new atoms.

How do atoms of different elements differ according to Dalton?

• They have the same mass and properties.

• They have different mass but the same properties.

• They have different masses and properties.

• They have the same mass but different properties.

What is the atomic number of aluminum?

• 13

• 27

• 9

• 19

What charge does a cation have?

• Negative

• Neutral

• Positive

• Variable

What is an example of isotopes in the element carbon?

• Carbon 10, Carbon 11

• Carbon 12, Carbon 13, Carbon 14

• Carbon 15, Carbon 16

• Carbon 17, Carbon 18

How do isotopes of the same element differ?

• In their electron configuration

• In their chemical properties

• In their nuclear properties

• In their atomic number

What did Dalton believe about atoms of the same element?

• They have different nuclear properties.

• They have different chemical properties.

• They are identical in mass and properties.

• They are always different.