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A Greek philosopher who theorized that all matter could be reduced to particles that could not be divided, which he described as "atomos."
All atoms were small, hard particles and made of a single material formed into different shapes and sizes.
He disagreed with Democritus, believing that you would never end up with a particle that could not be cut.
English chemist who developed the Atomic theory of matter through an experiment of gases. His theory states: A) All elements are composed of atoms and atoms can't be divided or destroyed. B) Atoms of the same element are exactly alike and atoms of different elements are different from each other. C) The atoms of 2 or more elements can join together to form types of matter called compounds.
Atoms are small particles that can not be ________ according to Dalton.
created, divided or destroyed.
J.J Thomsons model of an atom, in which he thought electrons were randomly distributed within a positively charged cloud
Chocolate chip ice-cream model
What one might call today a model of an atom proposed by J.J. Thomson because he thought that electrons were mixed throughout an atom
From his gold foil experiments, he knew some substances give off + charged particles called alpha particles, most of the mass of an atom is in the nucleus, he reasoned that electrons in the atom are whirled around outside the nucleus, most of the atom is empty space
Discovered nucleus and the fact atoms are mostly empty space with a dense nucleus.
When this happened in the gold foil experience, it helped Rutherford discover the nucleus.
discovered that electrons move around the nucleus in orbits called electron clouds. Also proposed that electrons
neutrons are a little more massive than
protons. But the difference is small, they are still about 1 amu.
isotopes of hydrogen
They all have one proton, but they can have different numbers of neutrons in their nucleus.
If you write carbon-12 and you know the atomic number for carbon is 6, how many neutrons does it have?
If you write carbon-10 and you know the atomic number for carbon is 6, how many neutrons does it have?
If you write carbon-14 and you know the atomic number for carbon is 6, how many neutrons does it have?
gravitational force in atoms
this pulls objects together. Because particles in atoms are very small, the gravitational force within atoms is small.
electromagnetic force in atoms
This is the force which causes particles with the same charge to repel each other and causes particles with opposite charges to attract each other.
This is an important force in radioactive atoms, helping to change neutrons into a proton and an electron.
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