Question

name: handwriting date: handwriting class: handwriting
unit: atomic structure
\history and structure of the atom\ - ws #1
directions: please answer each question to the best of your ability.

1. when was the idea of an atom first developed? describe this theory.
2. in your own words, state the 4 major ideas of dalton’s atomic theory.
3. which of these statements would dalton have agreed with? use dalton’s your answer.

a) atoms are the smallest particles of matter.
b) the mass of an iron atom is different from the mass of a copper atom.
c) every atom of silver is identical to every other atom of silver.
d) a compound is composed of atoms of two or more different

Explanation:

Question 1

The idea of the atom was first developed in ancient Greece (around 400 BCE) by philosophers like Democritus. His theory stated that matter is made of indivisible, indestructible particles called "atoms" (from "atomos," meaning uncuttable), and different atoms have different shapes/sizes.

1. All matter is made of tiny, indivisible atoms.
2. Atoms of the same element are identical (mass, properties); different elements have different atoms.
3. Atoms can’t be created/destroyed in chemical reactions.
4. Compounds form when atoms of different elements combine in fixed, whole - number ratios.

• a) Dalton thought atoms were the smallest matter particles: agrees.
• b) Dalton said same - element atoms have same mass, so iron and silver (different elements) have different masses: agrees.
• c) Dalton’s theory stated same - element atoms are identical: so every silver atom is identical: agrees.
• d) Dalton said compounds are atoms of different elements in fixed ratios: agrees (since it’s a combination of different atoms).

So a, b, c, d (depending on strict interpretation, but all align with Dalton’s core ideas).

Answer:

Around 400 BCE (ancient Greece, by Democritus). Theory: Matter is made of indivisible, indestructible "atoms" with different shapes/sizes.

Question 2