2.2 Basic Atomic Structure

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The smallest particle of an element that still retains the chemical properties of that element.
electrons, protons, neutrons
3 subatomic particles atoms are made of
1.Possesses negative electrical charges.
2.Are found orbiting the nucleus of an atom (the electron cloud)
3.Are 1/1837th of the mass of a single proton or neutron
1.Possess a positive electrical charge.
2.Are found clumped together within the nucleus of an atom.
3.Has a mass of 1 atomic mass unit (AMU) or 1 Dalton (Named after John Dalton.)
1. Possesses no electrical charge and are therefore referred to as neutral.
2. Are also found clumped together within the nucleus an atom.
3. Has a mass of 1 AMU or 1 Dalton.
Nuclear forces
These are short-range proton-to-neutron OR proton-to-proton OR neutron-to-neutron attractive forces that help hold together the nucleus of an atom.

These forces are greater than the repulsive same charge electrical forces exhibit by protons.

Atomic theory 1
All matter is composed of extremely small particles called “atoms”.
Atomic theory 2
Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties.
This has since been modified based on isotopes and ions.
Atomic theory 3
Atoms cannot be subdivided, created, or destroyed.
a. This has since been modified based upon current studies in quantum physics. Such examples include muons and quarks.
Atomic theory 4
Atoms of different elements combine in simple different ratios to form chemical compounds.
Atomic theory 5
In chemical reactions, atoms are combined, separated, or rearranged.
Dalton’s main flaws in the atomic theory
Atoms are not indivisible. The are divisible into several subatomic particles.
All atoms of a given element may not have identical properties as their masses may vary slightly (ie. isotopes).
Categories: Atomic Physics