Prelims - Evolution of Atom

smallest piece of matter, not to be cut, indivisible

Believed that matter could not be divided indefinitely?

Believed that matter could be divided into smaller and smaller pieces forever

Proposed the hook and eye model of atom based on experimentation and not on pure reason; There are elements that can be easily combined/separated; Also believed that atom is the smallest unit

atoms cannot be created nor destroyed

all matter is made of atoms

It is crucial for the successful interaction of two atoms.

First proposed that atoms are divisible; Found that atoms could sometimes eject a far smaller negative particle, the electron, while working with a cathode ray tube

When was electron discovered?

The term before for electrons

JJ Thomson developed this model of atom

The plums represented what?

The pudding represented what?

He introduced that the positive electrification mentioned by Thomson is a small dense center he named nucleus; He is considered the Father of Nuclear Physics; He also discovered the proton

When was nucleus discovered?

When was proton discovered?

describes the atoms as containing a small, dense, + charged center, known as the nucleus, with - electrons orbiting a nucleus in set, predictable paths

Who discovered the Nuclear Model of an Atom?

A Danish scientist that proposed an improvement by placing each electron in a specific energy level

When did Niels Bohr proposed an improvement by placing each electron in a specific energy level?

Electrons can move up a level if given enough energy. What is the so-called energy?

Electrons can move up a level if given enough energy. What is the so-called movement of electrons?

Electrons move in definite orbits around the nucleus, much like planets circle the sun . These orbits, or energy levels, are located at certain distances from the nucleus.

Who proposed The Planetary Model of Atom?

An Austrian physicist that used mathematical equations to describe the likelihood of finding an electron in a certain position; Also introduced the concept of sub-energy levels (s,p,d,f...)

Describes the likelihood of finding an electron in a certain position. This atomic model is known as the

Other term for Quantum Mechanical Model

When was Quantum Mechanical Model proposed?

Who discovered the neutron? He was also awarded a nobel prize in physics for this discovery.

Mentor of James Chadwick