Atomic Theories
Who was the first person to suggest that matter is made of tiny particles called atoms?
Democritus
What is the modern model of the atom?
It shows electrons moving in regions around the nucleus.
Define Neutron
A neutron is a subatomic particle with no electric charge (neutral) and a mass slightly greater than that of a proton
Who first suggested that matter is made of tiny particles called atoms?
Democritus.
What are the three main parts of an atom?
Protons, neutrons, and electrons.
Who developed the first modern atomic theory?
John Dalton
What is found in the nucleus?
Protons and neutrons.
Define Proton
A proton is a stable subatomic particle with a positive electrical charge that lives in the center of every atom.
Who developed the first modern atomic theory?
John Dalton
What charge does a proton have?
A positive charge (+).
Who discovered the electron?
J. J. Thomson.
What is an electron cloud?
The region where electrons are most likely to be found.
Define Nucleus
The atomic nucleus is the small, dense, and positively charged region located at the center of an atomic nucleus, containing nearly all of the atom's mass.
What did J.J. Thomson discover?
The electron.
What charge does a neutron have?
No charge; it is neutral.
Who discovered the nucleus of the atom?
Ernest Rutherford.
What charge does an electron have?
A negative charge.
Define Isotopes
An isotope is a variant of a chemical element that has the same number of protons and electrons, but a different number of neutrons in its nucleus.
What did Ernest Rutherford discover about the atom?
The small, dense nucleus
What charge does an electron have?
A negative charge (−).
Who developed the atomic model with electrons in specific energy levels?
Niels Bohr.
Who helped develop the modern atomic model?
Erwin Schrödinger helped develop the quantum mechanical model of the atom.
Define Atom
An atom is the smallest unit of a chemical element that retains the chemical properties of that element
What did Niels Bohr discover about electrons?
Electrons move around the nucleus in specific energy levels.
Where are protons and neutrons located?
In the nucleus at the center of the atom.