Chapter 3 Quiz Flashcards
What is the law of conservation of mass?
It was proposed by Antoine Lavoisier and states that mass is neither created nor destroyed during ordinary chemical reactions or physical changes; the total mass of the reactants must equal the total mass of the products
What is the law of definite proportions?
It is the fact that a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or the source of the compound
What is the law of multiple proportions?
If 2 or more different compounds are composed of the same 2 elements then the ratio of the masses of the 2nd element combined with a certain mass of the 1st elements is always a ratio of small whole numbers
What are 5 points of Dalton’s atomic theory?
1). All matter is composed of extremely small particles called atoms
2). Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, & other properties
3). Atoms cannot be subdivided, created, or destroyed
4). Atoms of different elements in simple whole number ratios form chemical compounds
5). In chemical rations, atoms are combined, separated, or rearranged
What 2 points of Dalton’s theory remains true?
1). All matter is composed of atoms
2). Atoms of any one element differ in propertied from atoms of another element
What did Democritus contribute?
He proposed that all the matter is composed of tiny particles called Atomos and that these particles were indivisible. Chop up piece of matter until you reach the atomos.
What did Dalton contribute
He reasoned that elements were composed of atoms & that only whole numbers of atoms can combine to form compounds; his ideas are now called the Atomic Theory of Matter
What did J.J. Thomson contribute?
Studied the rays and proved that they were tiny negative particles being emitted from the metal atoms
- Dubbed these tiny particles “electrons
What did Millikan contribute?
What did Rutherford contribute?
- Directed a narrow beam of alpha particles at a very thin sheet of gold foil
- Stated that all the positive charge and the mass is concentrated in a small core in the center of the atoms
The atom is mostly empty space with electrons surrounding the positively charged nucleus like planets around the sun
What did the gold foil experiment prove?
It proved that 1 in every 8000 positive alpha particles were deflected back toward the source from the thin sheet of gold foil.
How do we identify the number of protons, neutrons, and electrons in an atom?
Atomic number is the number of protons in an element.
Atomic mass is protons plus neutrons
Number of protons= number of neutrons
What is an isotope?
Refers to atoms that have the same number of protons but a different number of neutrons
