What was the earliest idea about atoms?

Democritus Introduces the Atom He thought that a point would be reached where matter could not be cut into still smaller pieces. He called these "uncuttable" pieces atomos. This is where the modern term atom comes from. Democritus first introduced the idea of the atom almost 2500 years ago.

What is the difference between old atomic theory and modern atomic theory?

Dalton's Atomic Theory vs Modern Atomic Theory Dalton's atomic theory is a theory about indivisible particles called atoms which are the smallest particles of all matter. Modern atomic theory is the theory that explains the fully detailed structure of an atom.

Why have ideas of atoms changed over time?

The atomic model changes over time because the atomic model was based on theories and discoveries.

How did early scientists recognize atoms?

The first modern evidence for atoms appears in the early 1800s when British chemist John Dalton discovered that chemicals always contain whole number ratios of atoms.

How have ideas of the atom changed?

Rutherford's experiment prompted a change in the atomic model. If the positive alpha particles mostly passed through the foil, but some bounced back. AND if they already knew that the electron was small and negative, then the atom must have a small positive nucleus with the electrons around them.

How did the model of the atom change as new evidence was discovered?

New experimental evidence may lead to a scientific model being changed or replaced. Before the discovery of the electron, atoms were thought to be tiny spheres that could not be divided. The discovery of the electron led to the 'plum-pudding model' of the atom.

How has the idea been modified by the modern atomic theory?

On the basis of new experimental facts, Dalton's atomic theory has been modified as: 1. Atom is no longer indivisible. Atom is composed of still smaller particles which are called electrons, protons and neutrons.

What is the modern theory of the atom?

Chemistry is based on the modern atomic theory, which states that all matter is composed of atoms. Atoms themselves are composed of protons, neutrons, and electrons. Each element has its own atomic number, which is equal to the number of protons in its nucleus.

How did the theory of atoms evolve?

Atomic theory originated as a philosophical concept in ancient India and Greece. The word "atom" comes from the ancient Greek word atomos, which means indivisible. According to atomism, matter consists of discrete particles.

Why is having a scientific model of the atom important?

Atomic models are important because, they help us visualize the interior of atoms and molecules, and thereby predicting properties of matter.

How did atomic theory develop and change?

In the early 1800s, the English Chemist John Dalton performed a number of experiments that eventually led to the acceptance of the idea of atoms. He formulated the first atomic theory since the “death of chemistry” that occurred during the prior 2000 years. Dalton theorized that all matter is made of atoms.

What made the scientists change the atomic models?

Rutherford's experiment prompted a change in the atomic model. If the positive alpha particles mostly passed through the foil, but some bounced back. AND if they already knew that the electron was small and negative, then the atom must have a small positive nucleus with the electrons around them.

How did atomic theory develop?

Democritus developed his atomic philosophy as a middle ground between two opposing Greek theories about reality and the illusion of change. He argued that matter was subdivided into indivisible and immutable particles that created the appearance of change when they joined and separated from others.

How are atoms of different elements different?

What makes atoms of various elements different from each other is their number of protons. In other words, each element is composed of atoms that have a specific number of protons.

Why has the atomic model changed over time quizlet?

In general, why did atomic theory change with time? Because more experiments gave more data, theories and models for atoms changed to be more accurate over time.

How is the modern model of an atom different from the Bohr atomic model?

Quantum model is considered as the modern model to describe the structure of an atom. The main difference between Bohr model and Quantum model is that Bohr model explains the particle behavior of an electron whereas quantum model explains the wave-particle duality of an electron.

How was the modern atomic theory developed?

In 1911, Ernest Rutherford developed the first coherent explanation of the structure of an atom. Using alpha particles emitted by radioactive atoms, he showed that the atom consists of a central, positively charged core, the nucleus, and negatively charged particles called electrons that orbit the nucleus.

What made the scientist change the atomic model?

Who made the earliest discovery about atoms?

John Dalton The idea that everything is made of atoms was pioneered by John Dalton (1766-1844) in a book he published in 1808.

How did the early philosophers view atoms and elements?

The atomic philosophy of the early Greeks Democritus believed that atoms were uniform, solid, hard, incompressible, and indestructible and that they moved in infinite numbers through empty space until stopped. Differences in atomic shape and size determined the various properties of matter.

What is the historical development of atom?

In the fifth century BC, Leucippus and Democritus argued that all matter was composed of small, finite particles that they called atomos, a term derived from the Greek word for “indivisible.” They thought of atoms as moving particles that differed in shape and size, and which could join together.

How did the concept of an atom evolved?

In the fifth century BC, Leucippus and Democritus argued that all matter was composed of small, finite particles that they called atomos, a term derived from the Greek word for “indivisible.” They thought of atoms as moving particles that differed in shape and size, and which could join together.

What is the development of atomic theory?

The atomic theory, which holds that matter is composed of tiny, indivisible particles in constant motion, was proposed in the 5th cent. BC by the Greek philosophers Leucippus and Democritus and was adopted by the Roman Lucretius. However, Aristotle did not accept the theory, and it was ignored for many centuries.

Which scientists developed the atomic theory?

John Dalton (1766-1844) is the scientist credited for proposing the atomic theory.

How do atoms of different elements differ quizlet?

Elements are different because they contain different numbers of protons. How do you find the number of neutrons in an atom? The number of neutrons in an atom is the difference between the mass number and the atomic number.

Who discovered atoms of different elements are different?

Scientist who contributed to the modern atomic theory.

Question	Answer
Atoms of different elements are different.	Dalton
Atoms of the same element are exactly alike.	Dalton
All substances are made of atoms.	Dalton
He wanted to know why elements combine is specific proportions.	Dalton

How is the modern atomic model different from Bohr’s model Why did scientists revise Bohr’s model?

1 Answer. Bohr thought that electrons orbited the nucleus in circular paths; whereas in the modern view atomic electron structure is more like 3D standing waves. Bohr built upon Rutherford's model of the atom.

Which scientists developed the first model of the atom that showed the structure of the inside of an atom?

Rutherford model, also called Rutherford atomic model, nuclear atom, or planetary model of the atom, description of the structure of atoms proposed (1911) by the New Zealand-born physicist Ernest Rutherford.

How do the Bohr model and the quantum mechanical model of the atom differ in how they describe electrons?

How do the Bohr model and the quantum mechanical model of the atom differ in how they describe electrons? The quantum mechanical model treats electrons as waves does not describe the electrons' path around the nucleus. The Bohr model treats electrons as particles traveling in specific circular orbits.