Question

john dalton (1766 - 1844):
john dalton was an english chemist. his ideas form the atomic theory of matter. here are his ideas.

• all elements are composed (made up) of atoms. it is impossible to divide or destroy an atom.
• all atoms of the same elements are alike. (one atom of oxygen is like another atom of oxygen.)
• atoms of different elements are different. (an atom of oxygen is different from an atom of hydrogen.)
• atoms of different elements combine to form a compound. these atoms have to be in definite whole number ratios. for example, water is a compound made up of 2 atoms of hydrogen and 1 atom of oxygen (a ratio of 2:1). three atoms of hydrogen and 2 atoms of oxygen cannot combine to make water.

1. what is the name of john dalton’s theory?
2. what are elements made of?
3. an atom of hydrogen and an atom of carbon are
4. what are compounds made of?
5. the ratio of atoms in hcl is: a) 1:3 b) 2:1 c) 1:1

Explanation:

1. The text clearly states "His ideas form the atomic theory of matter".
2. It says "All elements are composed (made up) of atoms".
3. As per "Atoms of different elements are different", hydrogen and carbon are different elements.
4. "Atoms of different elements combine to form a compound" indicates this.
5. HCl has 1 hydrogen (H) and 1 chlorine (Cl) atom, so the ratio is 1:1.

Answer:

1. The atomic theory of matter.
2. Atoms.
3. Different.
4. Atoms of different elements.
5. c) 1:1