Atomic models and theories Flashcards
___, ___, and ___ believed that matter is made up of primal matter.
Anaximenes, Heraclitus and Thales
___ also proposed that all materials are composed of four elements in different amounts.
Aristotle
___ and his teacher ___ proposed that matter is composed of very tiny particles that cannot be further divided.
Democritus, Leucippus
What is Atomos?
invisible bit of matter which became the basis for the modern word of the building blocks of matter called the atom.
They described Atoms to have ___ forms and they combined in different ways to give rise to different materials.
different
What was Dalton’s modern atomic theory?
Everything is made up of small indestructible and indivisible called atoms, Atoms of the same element are always identical, Different elements are different from any other element in their properties, When atoms of different elements combine, they form chemical compounds, atoms do not change. They can not be destroyed or created.
What are the drawbacks of Dalton’s theory?
Atoms are not indivisible, atoms of the same element can differ, consists of sub-atomic particles, isotopes- atoms of the same element that differ in the number of neutrons.
What are the Atomic Models?
Solid sphere, Plum pudding, Nuclear, Planetary and Electron.
What was the first atomic model and who/when was developed it?
Solid Sphere, John Dalton, in early 19th century
What did John Dalton hypothesized about the Solid sphere model?
An atom is a solid sphere that could not be divided into smaller particles.
Who discovered the Plum Pudding model and when did he created it? What did he also discovered?
J.J Thomson, in the late 1800s, electrons
How did J.J. Thomson discovered electrons?
Using cathode ray tube, he reasoned that the electric current was made of small particles called corpuscles.
Who discovered the Nuclear model and when was it discovered? What did he also discovered?
Ernest Rutherford, 1911 and discovered protons.
How did Ernest Rutherford discovered the Nuclear Model?
Using an alpha particle emitter and a thin gold foil sheet, he found out that not all alpha particles weren’t deflected at all.
Who discovered the Planetary model? Also describe the Planetary model.
Neils Bohr, protons and neutrons are both on the center, electrons travel in separate orbits around the nucleus.
Who discovered The Electron Model or Cloud model? And when was it discovered?
Werner Heisenberg, 1927
Describe the Electron model.
Shows both protons and neutrons are still in the middle while electrons still travel around but in the cloud form.
What are ions?
An atom or a molecule with a net electric charge due to the loss or gain of one or more electrons.
How is an Ion formed?
If electrons are removed from or added to a neutral atom, the same element will become a charged particle and Ion is formed.
What are the two types of Ions?
Cations and Anions
What are Cations?
Ion with a positive charge, when electron is removed
What are Anions?
Ion with a negative charge, when electron is added
What is Atomic Number?
represents the number of protons and electrons, serves as numeric identity of an element therefore, no two elements have the same atomic number. Capital letter Z is the symbol.
All atoms of the same element have the same number of protons and electrons thus, same Z. True or False?
True
What is Atomic Mass?
The sum of proton and neutron number. Symbol is capital letter A. Atoms of the same element may have the same atomic number but the atomic mass/neutron may differ.
What are Isotopes?
Are elements with the same atomic number but differ in their neutron number and thus, differ in their atomic mass.
What are the three known isotopes of Hydrogen?
Protium Z-1, A-1
Deuterium Z-1, A-2
Tritium Z-1, A-3
How do you find the number of protons?
Same value as the Atomic number and electrons.
How do you find the number of Neutrons?
Atomic mass minus atomic number, proton, or electron.
How do you find the number of Atomic mass?
Atomic number plus neutrons, Protons or electrons plus neutrons.
