Question

name: riley sanchez date: class period:
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.

(handwritten: was first developed around 400 b.c, he became a greek philosopher)

1. in your own words, state the 4 major ideas of dalton’s atomic theory.
2. which of these statements would dalton have agreed with? use dalton’s law to explain 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 elements.
(option d is circled)

Explanation:

Question 1

The idea of the atom was first developed around 400 B.C. by the Greek philosopher Democritus. His theory stated that matter is made up of tiny, indivisible particles called "atomos" (meaning indivisible in Greek), and these atoms are in constant motion in a void (empty space). Different types of matter have different types of atoms, and the properties of matter are determined by the atoms that compose it.

Dalton's Atomic Theory has four major ideas: 1. All matter is composed of extremely small, indivisible particles called atoms. 2. Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in these aspects. 3. Atoms cannot be created, destroyed, or subdivided in chemical reactions. 4. Compounds are formed when atoms of different elements combine in simple, whole - number ratios.

• Statement a: Dalton's theory stated that atoms are the smallest particles of matter that take part in chemical reactions (though we now know atoms are divisible into sub - atomic particles, Dalton believed them to be indivisible). So Dalton would agree that atoms are the smallest particles of matter (in the context of chemical reactions as he knew it).
• Statement b: Dalton's theory said that atoms of different elements have different masses. Since iron and copper are different elements, their atoms would have different masses. So Dalton would agree.
• Statement c: Dalton's theory proposed that all atoms of a given element are identical in mass and properties. So every silver atom (same element) should be identical to other silver atoms, and Dalton would agree.
• Statement d: Dalton's theory stated that compounds are formed by the combination of atoms of two or more different elements in simple whole - number ratios. So Dalton would agree.

So Dalton would have agreed with statements a, b, c, and d. Let's explain each with Dalton's theory:

• For a: Dalton's theory considered atoms as the smallest indivisible particles of matter (in chemical reactions).
• For b: Atoms of different elements have different masses (part of Dalton's theory), so iron and copper atoms (different elements) have different masses.
• For c: Atoms of the same element are identical (part of Dalton's theory), so all silver atoms are identical.
• For d: Compounds are made by combining atoms of different elements (part of Dalton's theory), so a compound has atoms of two or more different elements.

Answer:

The idea of the atom was first developed around 400 B.C. by the Greek philosopher Democritus. His theory proposed that matter consists of tiny, indivisible particles called atoms, which are in constant motion in empty space. Different substances have different kinds of atoms, and the properties of matter depend on the atoms that make it up.

Question 2